Justice Minister Katsuyuki Kawai has told reporters after submitting his letter of resignation that judicial administration cannot afford to lose the public's trust.
Kawai submitted his resignation letter to Prime Minister Shinzo Abe on Thursday morning. It followed reports that the office of his wife, Anri Kawai, who was elected to the Upper House in July, made payments to campaign staff over the legal limit.
Kawai told reporters after meeting Abe that the post of justice minister involves huge responsibilities.
He said neither he nor his wife knows anything about what's being reported, and that he believes his political and campaign activities were in accordance with the law.
He promised to reveal the facts and fulfill his accountability.
Kawai said he decided to step down on Thursday morning after consulting with his wife, because public trust in judicial administration cannot be lost even for a minute.