The man Virginia Republicans dared to come to dinner in the state will come.

Vice President Walter F. Mondale, whose Virginia travel expenses state Republicans once said they would pay, will kick off Democrat Henry E. Howell's campaign for governor in Northern Virginia on Aug. 29, the Howell staff said today.

Although conceding their campaign is in urgent need of money, the Howell staffers said the decision to bring Mondale into Virginia was made independently of the Republican expense offer.

Apparently confident that the Vice President is unpopular in the state, Republican John N. Dalton's gubernatorial campaign said in a recent publication it would pay Mondale's costs if he "spoke for Howell." Dalton spokesman Richard Lobb said today that the offer was made "tongue-in-check." But said that the Dalton staff "would like him (Mondale) to go a little farther south" in the state than McLean.

Mondale will appear there at $125-a-person dinner and reception at Salona, the home of State Sen. Clive L. DuVal II, a long-time Howell supporter. Between 250 and 500 people, about half of them from Northern Virginia, are expected for the dinner, a Howell aide said.

Mondale is the first of many major Democratic party officials, including President Carter, whom the Howell campaign has said it plans to bring into the state this year to campaign for Democrats before the No. 8 election. William Rosendahl. Howell's state manager, said such events should rise between $25,000 and $100,000 for Howell's treasury, depleted by costs of the June 14 primary.

Sen. Hubert H. Humphrey (D-Minn.), another of Howell's long-time Washington friends, will speak at a second major fund-raiser Sept. 8 in Norfolk. Tickets for that dinner will be priced about the same as the Mondale dinner, a Howell official said.

Neither is "an event for the average person," said Kevin Mullin, a deputy Howell manager. But Howell's finances are "not in the best shape . . . right now" and later events in the campaign will be less expensive, he said.

"We're not responding to Johnny Dalton at all," said Rosendahl. "We think it's a great honor to have the Vice president and President interested in our state."