The United States has offered anti-missile technology to Japan in exchange for technology that U.S. business could use.

The proposal, outlined last week to Japanese officials in Tokyo by a top U.S. defense official, represents a novel effort by Washington to use American defense know-how to help civilian industry.The offer grew out of Japanese officials' alarm about the testing of a North Korean missile capable of hitting Japan with chemical, biological and nuclear warheads. The missile was tested earlier this year, according to U.S. intelligence.

Still, it remained unclear whether Japanese companies would be willing or able to hand over valuable technology, and whether Japan's government - which includes ministers with strong pacifist leanings - would commit itself to an anti-missile program.

In his talks with Japanese defense officials, John M. Deutch, undersecretary of defense for acquisition and technology, said he asked for Japanese cooperation in building an anti-missile system that would respond to missiles both in and above the atmosphere.

The United States is spending $12 billion over the next five years on the system, known as Theater Missile Defense.

In Japan's case, Mr. Deutch said, the United States is seeking a ''technology-for-technology arrangement." Washington and Tokyo would jointly develop an anti-missile system, with military technology flowing to Japan in the process.

In return, Japanese private companies working on the joint project would pass along technology with both military and commercial applications to American companies, he said.

Japanese officials put off giving an answer to the American proposal, saying study was needed.

Mr. Deutch said the United States does not have an "abrupt timetable" for its "new and adventurous" idea.

Even if Japan were willing to give U.S. companies "dual-use" technology, it was not certain whether the private Japanese companies working on the anti- missile defense would have such technology.

And Japanese companies might be loathe to give important commercial secrets to U.S. competitors.