A funny thing happened to Jesse Helms on his way to becoming one of the Senate's leading skinflints and bureaucrat baiters.

He became the biggest spender in any Senate campaign in history, and the head of a campaign bureucracy so large it takes half an office building to house it.

He's also been christened "The Six Million Dollar Man," hardly the kind of nickname coveted by a man who has spent most of his life railing against big spenders in Washington.

Helms, North Carolina's first Republican senator in the 20th Century, earned the title raising $6.7 million in campaign funds, or $3 per voter. This eclipses the previous spending record set by Sen. H. John Heinz III (R.Pa.) by more than $3 million. "We've become bionic," campaign manager Thomas Ellis declared when the fund-raising total surpassed $6 million.

Helms, who frequently introduced as "this country's leading conservative spokesman," is slightly embarrassed by all the millions. "I wish we could run our campaign on a dime," he said last week. "But if you're a Republican in a state where Democrats outregistered you 3-to-1, you have to scratch and do whatever you have to win."

Not surprisingly, John Ingram, the Democratic Senate nominee, has seized on the money issue. Hardly an hour goes by without him ranting about "my Six Million Dollar Man opponent" and "His ties to big money, big oil and big insurance special interests."

Helms has outraised and outspent Ingram, a populist state insurance commissioner, by 32 to 1. "If he had a record of fighting for people like I do, he wouldn't need $6 million," Ingram declares. "But he has a record of being against our young people, our senior citizens, our farmers. our veterans and our working people."

The attacks are doing Ingram some, but not enough good.A poll conducted for the Charlotte Observer last week found that 40 percent of the state's voters think Helms is spending too much money on his reelection. The same poll, however, found Helms leading his Democratic challenger by a commanding 50-to-32 percent.

One reason the spending issue may not be doing more damage to Helms is his campaign doesn't look lavish on the surface. Almost half of the $6.7 million raised has gone to firms controlled by Richard Viguerie, of Falls Church, Va., who put together Helm's direct mail fund-raising effort.

The campaign is not big on traditional election paraphernalia. There are no Helms billboards. Yard signs won't be put until after Halloween. The advertising budget is large enough - $300,000 - to flood the airways with television endorsements from New York Yankee pitcher Jim (Catfish) Hunter, Cy Young award winner Gaylord Perry, and race trackdriver Richard Petty, but not outlandish by North Carolina standards.

Looks are deceiving. They conceal what has been described as the most sophisticated and smoothest campaign in North Carolina history.

The Helms campaign claims 150 paid staff members, working out of two floors of a Raleigh office building and 20 other locations. Six are bookkeepers who keep track of the money flowing in; four do little more than arrange the senator's schedule; eight send out news release and tapes to 25 television station's and about 600 smalltown newspapers and radio stations around the state.

What's unusual and expensive about Helms' campaign is its direct mail and computer operation. Every one of North Carolina's 2.2 million voters is listed on the computer, by name, precinct, registration and voting history.

By election day, the Helms camp hopes its 60,000 volunteers will contact as many of these 2.2 million people as possible, either in person or by telephone. Many others will recieve highly personaliezd letters.

One letter, for example, asks the receiver to pass out Helms leaflets. "As you know, Jesse can't count on the liberal news establishment to carry his message to voters," it says. "He must rely on your help to make sure the voters hear both sides of the story."

Another states: "George Meany's union kingpins have lashed out at me because of my work to preserve a worker's right to earn a living without being forced to join a union. Liberal activists who would cripple our national defense are out for my political hide. And because of my criticism of Joe Califano and my opposition to the Panama Canal giveway, the president of the United States has come to North Carolina twice to campaign against me."

he Carter White House would love to see Helms, one of the administration's most vocal foes, defeated. So would organized labor and much of the state's moderate Democratic establishment.

To hear some of them talk, Helms is "Senator No," a man seldom for anything, an obstructionist, a blemish on the state's reputation for racial moderation.

(Race has not been an isue this fall, although Helms got in hot water for saying he recieved a "get worse" letter from U.N. Ambassador Andrew Young after he had a back operation. "Andy Young said some of his friends in Africa wanted to have me for dinner," Helms was quoted as saying. Helms also said he'd received a letter from Sen. George McGovern (D.S.C.). He claimed it said, "Come back. All has been given away.")

Earlier this year, the moderates hopefully talked of 1978 as watershed year, a time when North Carolina would decide if it is part of the "progressive New South," or a museum of the mossback, race-baiting politics of the Old South.

One hears little of that same talk this fall. Ingram upset that Democratic establishment's candidate, banker Luther Hodges Jr., in a bitter May runoff. Many traditional loyalists have been slow to flock to the Ingram banner because of his populist rthetoric.

The Charlotte Observer, for example, reported that more than 50 of the 165 influential Democrats Gov. Jim Hunt keeps on a secret list refused to buy or help sell tickets for an Asheville reception for President Carter last month because the proceeds were to go to Ingram. Four former Democratic state chairman have endorsed Helms.

Hunt and other partly leaders have tried to counter this. But it is hard to gauge how much headway they've made.

Ingram, a maverick who has spent most of his political career outside regular party circles, casts himself as a "people's candidate." He is trying to fashion a victory margin from a coalition of traditional Democrats, blacks, young people and what's called the "redneck vote" here.

On the stump, Ingram talks more about insurance overhaul, a matter that seldom comes up in the Senate, than any other issue facing the nation. He repeatedly links Helms to Richard M. Nixon, and reminds voters of the billboards Helms used in his 1972 campaign that said, "Nixon Needs Him."

This has some appeal in the land of Sam Ervin, the chairman of the Senate Watergate committee. But how much is in doubt. It's also questionable how much inroad his attacks on Helms, and special interest groups he claims are financing Helms' campaign, are having.

The charge stands up only in part, Traditional conservative groups, such as the National Rifle Association and the American Conservative Union, as well as major oil companies, such as Ashland, Texaco, Getty and Shell, have contributed heavily to Helms' campaign. But their donations amount to less that 10 percent of the $6.7 million he has raised.

The rest has come 19,000 small donors, more than half outside North Carolina. Helms' message of unabashed patriotism and tight-fisted conservatism is to their ears.

"I envy the citizens of North Carolina, I only wish you were representing California," one 83-year-old wrote from Yucaipa, Calif. "It is good to know that there is a staunch "tarheel" fighting the deplorable enchroachment of self-interest union bosses, and the unrealistic, idealistic young lawmakers," wrote a person from Dallas. "I want to contribute something with the hope that our our beloved God's chillun' will have a more equitable deal."