A Montgomery County district court judge yesterday acquitted a 62-year-old member of the Progress Club, an all-male social club in Rockville, on a charge of "betting on the result of" a poker game.

After a two-hour hearing in which the prosecution called three witnesses and the defense none, Judge Cornelius Vaughey said the state had not proven that Lawrence I. Kasdon of Bethesda bet in a poker game the night of June 5, when Rockville police raided the club and arrested him and 20 other mostly elderly men on charges of illegal gambling.

State's attorney Andrew L. Sonner, said later in a telephone interview that he was "surprised" by the judge's ruling.

"It's no big deal," Sonner said. "But everybody conveniently forgot whether he had bet that night."

Of the 21 club members or employes arrested in the raid, only Kasdon pleaded not guilty in order to go to trial. The others, including Washington restaurateur Duke Ziebert and former Washington Bullets part owner Arnold A. Heft, opted for guilty pleas and performed community services.

But the corporation that runs the club went on trial last November on six charges of illegally running a place to gamble. After a four-day trial, a Montgomery jury was unable to reach a verdict and a mistrial was declared. A new trial is scheduled for Feb. 13.

Yesterday, after hearing the testimony of a Rockville policeman, the club's former manager and the maitre d' at Ziebert's Connecticut Avenue restaurant, Vaughey likened the state's case to his son's high school football games, where people see the boy dressed to play but cannot remember whether he played or just warmed the bench.