President Reagan, in recommending 50 percent pay increases for members of Congress, judges, and other top federal officials, inadvertently recommended a 56 percent boost in his pension, a White House spokesman said.

Under federal law, former presidents receive annual pensions equal to the salaries of Cabinet secretaries. Reagan recommended that Cabinet secretaries' annual salaries rise from $99,500 to $155,000.White House spokesman B. Jay Cooper said Reagan was unaware of the pension implications when he recommended the salary increases to Congress. Cooper said he doubted the information would have changed Reagan's mind, "the other factors being so overwhelming."

Reagan already receives a $29,711 annual pension as a former governor of California.

Former Presidents Jimmy Carter, Gerald R. Ford and Richard M. Nixon would receive the pension increase as well, according to David Keating, executive director of the National Taxpayers Union. The union said in a news release more than a month ago that it had raised the issue in a letter to Reagan.

Reagan proposed that the salaries of members of Congress and judges be increased from $89,500 to $135,000 a year. Similiar 50 percent increases were recommended for assistant secretaries and bureau directors as well as the vice president and speaker of the House.

The raises will go into effect automatically, under special legislation, unless voted down by both houses of Congress within 30 days of Monday, when the recommendation is to be submitted to Congress with the budget.