"After continued consultations with Iraq, we have come to believe that the situation in Iraq has gradually improved and that we are gradually achieving the purpose," he said.
"The Iraqi side is reaching out to countries concerned to co-ordinate what it wants to ask of multinational forces from the next year," he added. "I believe Iraq is showing its understanding for Japan's thinking."
The mission was the last Japanese military operation in Iraq after Japan, which has been officially pacifist since the end of the Second World War, pulled out its ground troops in 2006.
The deployment was the first by the Japanese military to a combat zone since 1945.
Komura said the government would continue with another controversial mission in the Indian Ocean, in which Japanese naval forces provide fuel for US-led forces in Afghanistan.
The deployments in the Indian Ocean and Iraq have been heavily criticised by Japanese opposition politicians who argue that Japan should not be part of "American wars".