Rockville Mayor John R. Freeland, who for four months has been at the center of a fierce controversy for accepting a job with a city developer, said yesterday he will resign from office within a month,.

Freeland said he will resign because a promotion he expects from his employer, Eisinger-Kilbane and Associates, would take up some of the time he wants to spend with his wife Marilyn, who is suffering from cancer, according to City Council member Douglas M. Duncan.

"There was little or no choice on my part to give Marilyn all the support I possibly could," Freeland said. "Marilyn is No. 1 in my life. She needs me, and we feel there is no other alternative."

Freeland said the controversy over his job with Eisinger-Kilbane played no part in his decision.

"I hate like hell to do what I did, tell the council I'm going to leave," Freeland said. "But I do have a private life. It has nothing to do with the flak I received. I stood up to that."

It will be up to the council to decide whether to pick one of its own members to fill the vacancy or to offer the $8,000-a-year job to someone not involved in city government, city officials said.

Since Freeland accepted a top-level position in June with Eisinger-Kilbane, critics charged that his job is a conflict of interest because the firm often needs city approval on projects.

Among its projects is the $40 million Rockville Mall. The controversy over the mayor's job, critics said, was diverting the council's attention from city business.

Supporters of the mayor, including council member Stephen N. Abrams, said they saw no conflict because Freeland has abided by the city's ethics ordinance in disclosing his relationship with the firm.

Duncan, a former political ally of the mayor who last month, along with council member Viola Hovsepian, called for Freeland's resignation, said the mayor's decision was "anticlimatic."

Although Freeland had pledged to refrain from any city transactions involving Eisinger-Kilbane, he had said that he would resign only if a majority of the four-member City Council demanded it, or if provisions in the city's ethics ordinance, now being revised, called for it.

Political observers said they were not surprised by the news of Freeland's decision, which was reported in the Montgomery Sentinel yesterday.

"I wasn't terribly surprised, but I'm sorry it had to come to this," said M. Thomas Lawrey, chairman of the longtime ruling Independents for Rockville, Freeland's party for the past 12 years.