Michael E. Norris, Republican candidate for sheriff in Alexandria, said yesterday he will resign from the city police force, ending his four-month bout with police department regulations that prohibit him from working as a policeman while campaigning.

Norris said at a press conference yesterday that his resignation will become effective Sept. 1. He said that he made his decision on the professional grounds that his "quest for the office of sheriff" should be separate from his job as police sergeant.

After Norris announced his candidacy for the Republican sheriff's nomination last April, Police Chief John B. Holihan (who has since announced his retirement) told Norris he would have to quit because of departmental regulations prohibiting police officers from running for office.

Norris, 28, took the matter to court, A Circuit Court judge said the regulations were vague and unconstitutional.

The day after Norris won the June Republican primary Holihans put into effect a rule that prohibits officers from "becoming candidates or campaigning in any partisan primary election or becoming a partisan candidate and so campaigning in any election."

Norris is opposing Democratic sheriff candidate Patrick J. Holland, a real estate investment manager, in the general election Nov. 8.