Midge Costanza, the presidential adviser whose colorful comments and brash outspokenness became an increasing irritant to top White House officials, has resigned.

Costanza informed President Carter of her decision Monday, a week after her scheduled appearance on ABC-TV was abruptly canceled by Carter media advisers who had grown weary of her attention-getting performances.

President spokesman Rex Granum said Carter accepted the resignations "with regret" but asked her to stay on for an undetermined time to allow for a smooth transition.

Granum said the resignation was "a completely voluntary act" on Costanza's part.

In a letter to Carter, confirmed by Granum. Costanza wrote: "Although we share common goals and concerns, it has become clear that our approaches to fulfilling them are different.

"My own approach has been largely one of advocacy. I have sought to advise you on the concerns assigned to me and to present those interests and needs to you.

"There are those who suggest that I should have simply carried out your policies and not voiced my own opinions and ideas openly. But that was not my style, my experience or my interpretation of how I could best serve you and your constitutents."

Costanza's office said last night that she had left town on vacation and could not be reached for comment.

However, in an interview with Helen Thomas of United Press International, she said she was "not sad. I'm not angry with anyone. No one asked me to go. In fact, the president asked me to stay. I have such confidence that what I have done is right. I still respect and love Jimmy Carter."

Costanza, a former vice mayor of Rochester, N.Y., joined Carter's presidential campaign in its earliest stages.

She was rewarded with a highly visible, $56,000-a-year job as "public liaison" for the president, responsible for White House relations with numerous constituent groups.

For a time, her office was down the hall from the president's. In a symbolic fall from grace in May, she was moved into the basement.

At that time the bulk of her job was given to Anne Wexler, a liberal Democratic Party activist. Costanza was assigned to handle women's issues, particularly passage of the Equal Rights Amendment.

She said that during this period she was often asked "how long I would take" such treatment. As late as last week she said she had no intention of resigning and that her "treatment was not half important as the goals. I have a job to do here and I intend to do it. I work for the president of the United States and until and unless the president is not pleased with my performance, I will stay."

Costanza was hardly the conventional image of a White House aide. She was a hugger and a kisser who would have her picture taken squeezing White House guards.

When others around the president were holding firm during the controversy surrounding former budget director Bert Lance, Costonza said publicly she thought he should resign.

She and her staff saw almost anyone who asked to be seen, from poet Allen Ginsberg to opponents to B1 bomber, and she was almost always available for press interviews.

Some White House insiders had privately come to refer to her as "a flake." And the recent cancellation of her television appearance was used as an example of a new sense of discipline within the sometimes undisciplined Carter White House.