The editor of a military affairs magazine told a House panel yesterday that a story about the Pentagon's recently disclosed "Stealth" break through was leaked to him by a high-level Defense Department official.

Benjamin Schemmer, editor of the Armed Forces Journal, told the House Armed Services subcommittee on investigations that he felt the action was "a directed leak for political purposes because I can think of no reason why this story should be made known at this time." He also termed the action "totally irresponsible."

Defense Secretary Harold Brown announced last Friday that the United States had achieved a major technological breakthrough, dubbed "Stealth," that would prevent Soviet radar or other sensors from spotting American aircraft until it was too late to knock them down.

Schemmer said after the hearing that he was briefed by a "senior defense official," whom he declined to name, at least two days before the full House and Senate Armed Services committees were informed of the project. Committee members "were sworn to ultra-secrecy while the magazine was at press," he said later.

There had been leaks in other publications about some details of the project. Schemmer said he was given the impression that the Defense Department "wanted the story out because of previous leaks about Stealth."