A lawyer who has worked for 12 years in the office of the Pentagon's general counsel has been fired from that office for giving advice to a leading critic of SAT II, the Pentagon confirmed yesterday.

The lawyer, Harry H. Almond Jr., gave textual suggestions on the treaty to retired Lt. Gen. Edward J. Rowny for a letter Rowny was drafting to Frank Church (D-Idaho), chairman of the Foreign Relations Committee. A copy of Rowny's letter with Almond's marginal notations was found in a Pentagon Xerox machine by one of Almond's associates, who apparently passed it on to their mutual section chief, Brent Rushforth. Rushforth told Almond he was being terminated later the same day.

Rushforth declined to discuss the episode on the record yesterday. A Pentagon official said it was "the grossest kind of impropriety" for Almond to give help to Rowny when the retired General was working to defeat the strategic arms limitation treaty and Almond's bosses in the Pentagon were working for its ratification.

Another Pentagon official said the Defense Department regarded Almond as a competent employe and wanted to help him find a job elsewhere in government, perhaps in the Defense Department itself.

A copy of the Rowny letter with Almond's marginal notations, supplied to The Washington Post by Almond's attorney, shows that his comments involved fine points of law or language. The letter was meant as an addition to Rowny's personal testimony on SALT II, and concerned Soviet negotiating techniques. Almond is planning to appeal his dismissal.