John B. Anderson and Ronald Reagan may go with a two-man debate if President Carter continues to refuse a three-way meeting, the two campaigns indicated today.

Anderson, the independent presidential candidate, told a news conference here he would prefer a three-way debate, but would be willing to face Reagan alone.

"As far as I'm concerned, any debate is better than no debate," the Illinois congressman said.

James Baker, a senior Reagan compaign adviser, later said that if the League of Women Voters, which is trying to sponsor a series of debates, finds Anderson qualified, "We think he should have his day in the sun."

Baker, interviewed on public television's MacNeil-Lehrer Report, said he was unwilling to "lock" Reagan into a commitment to a two-way debate with Anderson.

However, he indicated that such an appearance fits into current thinking in the Reagan camp. "We're not going to say we're going to be there . . . but we're leaning that way . . . we are leaning in the way of being there."

The statement puts renewed pressure on Carter to either include Anderson or risk being excluded himself as decision-making deadlines approach for the debate.

Appearing on the same nationally televised program, Robert Strauss, Carter's campaign chairman, maintained that the president is willing to include Anderson in later debates but wants to meet Reagan alone first.

"We obviously think our political fortunes are best served by a one-on-one meeting," said Strauss. "We think we'd dilute it with Congressman Anderson in it."

He characterized Anderson as "a minor candidate," lucky even to be considered for inclusion in debate with the nominees of the two major parties. He intimated that Reagan and Anderson forces are in collusion on the debate issue. "They're working very well together. They're both Republicans," Strauss said.

Anderson, an Illinois congressman, was a candidate for the Republican presidential nomination before announcing April 24 that he would run as an independent.

His status in the debate is still very much in the air. The League of Women Voters has said it will decide by Wednesday if he will be included. It has set a 15 percent standing in national polls as the key yardstick for inclusion.

Anderson scored 17 percent in the most recent national poll, one conducted by the Roper polling organization. But he has fallen below that in other recent polls.

A league spokesman said last night that it "would be prepared to go ahead with the debate" if only Reagan and Anderson were willing to participate.

The Carter campaign, fearing Anderson will siphon away Democratic voters, has sought out other groups to offer forums for an encounter solely with Reagan.

Anderson lashed out at this tactic today "By what right, by what objective standard does (Carter) seek to tell the American people to whom they should listen? . . . I believe I have something distinctive to offer the American people.

"I think it ill becomes a president or anyone else to try to circumscribe the rights of the American people to hear another candidate."

Anderson raised the debate issue during the last day of a five-day Midwest swing plagued by bad weather and minor snafus. Today, for example, Anderson's vice presidential running mate, Patrick Lucey, made an embarrassing admission here in the automobile capital of the nation. He said he drives a French-made Peugeot, not an American-made car. The car, he added, "is not a very valuable asset to our family, and I think it's less valuable to the campaign."

The snafus and the weather have been an irritant, diminishing crowds' enthusiasm and occasionally putting the candidate on the defensive.

Twice in the last 16 hours Anderson has taken to paraphrasing author Mark Twain, saying. "Let me assure you, reports of our political demise are premature."

Such statements have a dash of good humor, all the same, for Anderson finds other signs encouraging. After months of hard work and uncertainty, he now has a formal platform and a vice presidential candidate to run with.

Anderson is relaxed and comfortable on the stump. He is showing flashes of wit, which some thought him incapable of. Gone are the pomposity and sermonizing of early summer.

The crowds these last four days in his swing through the Midwest have been respectably if not overwhelmingly large, and friendly.

A new poll by Newsweek magazine reveals that a 71 percent majority supports his insistence on inclusion in any presidential debates.

And Thursday the Federal Election Commission will consider a staff recommendation that would make Anderson potentially eligible for federal subsidies to help finance his campaign. A federal court ruling on the same issue is expected within days.

If Anderson receives a favorable ruling from the FEC, he would qualify for public money only if he receives 5 percent or more of the November vote. His allocation would be based on his portion of the vote. If he received 5 percent, an FEC spokesman said, he would get about $5 million, compared with the $29.4 million that each major-party candidate automatically receives.

The Illinois congressman also said private contributions are rebounding; Tuesday's $165,000 was the biggest in a month.

"The money is coming in. Fear not. Fear not. We're going to have money to run this campaign," he said.

Later, he and Lucey, Democratic former governor of Wisconsin, addressed a lunchtime crowd of more than 2,000 at Kennedy Square in downtown Detroit.

In a state where Anderson has Carter strategist worried, he and Lucey made emotional appeals for the support of Democratic voters.Anderson charged Carter with 3 1/2 years of "mismanaging the economy of this country," and of issuing a new economic program every six months.

He had harsh words for Carter's latest such program, issued last week, in which the president boasted of a "bright new economic future."

"Let him tell that to the 30 or 35 percent of the auto workers in this state who are unemployed," Anderson said. "Let him tell that to maybe another 650,000 workers in the supply industries. Let him tell of his bright new economic promises to the millions of youths in our country who have never had a job."

Anderson's stop in Detroit completed a five-day swing through the industrial heartland where he must do well if his longshot but is to succeed.

During the trip, regional newspapers and television stations gave him almost equal treatment with Carter and Reagan.