The move is aimed at streamlining command in the event of a crisis, and procedures to send Japanese troops to peacekeeping and other missions, and to raise the country's global security profile.
The resolution, proposed by the ruling Liberal Democratic Party and approved by the opposition Democratic Party, has yet to be passed by the upper chamber. The agency could become a ministry and its director minister as soon as January.
The country's Communists and Social Democrats had opposed bringing the military out of civilian control, reflecting prevailing public sentiment. But concerns that consultation delays in the event of a security threat might prove dangerous had prompted the amendment.
International peacekeeping missions and military self-defense action outside Japan will now be compulsory, rather than supplementary, duties for the country's Self Defense Forces.
North Korea's announcement that it conducted its first nuclear test on October 9 provoked widespread calls in the Japanese leadership for stronger strategic defense capability.
