Nakagawa, a close ally of Aso, who denied being drunk, said he will quit after Parliament approves a supplementary budget probably in April.
Despite his denials, the Japanese minister had faced calls from the Opposition to be sacked when he appeared incoherent and slurred his speech at a press conference after the G7 meeting on the global economic crisis. The Opposition had also threatened a censure motion against him. Nakagawa, however, blamed a cold medicine for his drowsy appearance.
"I apologise for causing such a big fuss," he said after announcing his resignation, the Kyodo news agency reported.
"I visited hospital last night and this morning and was diagnosed with a bad lower back, cold and fatigue. I'll do my best to fulfil my duties for my remaining tenure. I hope the Japanese economy will recover as early as possible," the agency quoted him as saying.
His fellow ministers were unsparing with health minister Yoichi Masuzoe saying, "Looking after one's own health is part of the responsibility of a politician."
Transport minister Kazuyoshi Kaneko said, "I feel bad for him, but he shouldn't have spoken at the press conference."
Text: PTI
Image: Japanese finance minister Shoichi Nakagawa. | Photograph: Kim Kyung-Hoon/Reuters