An embattled City Council member, Dennis Gallagher, won a significant court victory yesterday when a state judge dismissed a rape charge the Republican of Queens had faced. The indictment was thrown out because of the conduct of prosecutors during the grand jury proceedings last summer.

The judge found prosecutors had asked improper questions about Mr. Gallagher’s sex life and had made the mistake of suggesting an elected official should be held to a higher standard of conduct.

The dismissal of the indictment is not necessarily the end of the matter. The judge, Sheri Roman, ruled that the evidence prosecutors provided “was legally sufficient to support each and every one of the counts,” which include rape and assault. Judge Roman said prosecutors in Queens were free to seek the same charges from the grand jury again. The Queens district attorney, Richard Brown, said his office intended to seek a new indictment.

Mr. Gallagher voluntarily testified before the grand jury investigating a sexual encounter between him and a woman that took place on a Sunday last July, in his Queens campaign office. When prosecutors cross-examined him, Mr. Gallagher was subjected to “improper questioning” that “was prejudicial” and attempted “to create improper inferences in the minds of the Grand Jurors,” Judge Roman ruled.

The court decision offers a rare glimpse inside the grand jury room, where an indictment requires the vote of only 12 of 23 jurors. The questions from prosecutors had concerned at least one grand juror present. Judge Roman said one juror had told one of the prosecutors, Kenneth Appelbaum, that the questions asked of Mr. Gallagher seemed “an attempt to make him look foolish.”

Judge Roman said Mr. Gallagher, one of three Republicans on the 51-member council, shouldn’t have been asked questions such as whether he was a “polished” public speaker or whether he tried “to present a certain prestige associated” with his office.

Questions such as those, Judge Roman said, were aimed to encourage the grand jury to hold Mr. Gallagher to a more “stringent standard” when deciding whether to indict.

Judge Roman also took issue with prosecutors asking Mr. Gallagher eight times whether he knew of any motive that would explain why his accuser would provide a false account. A prominent Queens defense attorney, Marvyn Kornberg, who is not connected to the case, said he has heard Queens prosecutors ask that same question in another grand jury proceeding involving a rape allegation.

There is no judge present while witnesses testify to a grand jury, meaning that attorneys have no immediate recourse to what they believe is improper questioning. But it is rare for an indictment to be thrown out later due to a line of questioning.

In a terse statement, the district attorney did not challenge Judge Roman’s decision. Mr. Brown, a former judge, said “the matter will be re-presented to another Grand Jury before which the defendant can once again, if he be so advised, testify.”

A lawyer for Mr. Gallagher, Benjamin Brafman said he was “hopeful that we will be able to persuade the district attorney’s office not to re-present this case because in our view there was never a rape and, accordingly, Councilman Gallagher should never have been prosecuted in the first place.”

Mr. Gallagher was voted out of his leadership positions last August after he was indicted. He insists the sex was consensual.

In interviews, constituents in Mr. Gallagher’s district, which includes Middle Village and parts of Ridgewood, were generally supportive of their council member yesterday.

“His personal life is his personal life, but as far as a councilman he is good,” the owner of Middle Village Deli, Simon Yoo, said. “I don’t know what happened,” he said when asked about the allegations against Mr. Gallagher. “I wasn’t there.”