Economic and fiscal policy minister Heizo Takenaka declared victory Sunday, with media polls showing he was set to win a seat in the House of Councilors.
Takenaka, chief architect of Prime Minister Junichiro Koizumi's reform policies, ran in the proportional representation section on the Liberal Democratic Party ticket.
"I believe voters gave support to (Koizumi's) reforms of the past three years," Takenaka said at his election office in Tokyo. "I have been a minister to push for financial and fiscal reform, but now as a Diet member, I would like to also work on other reforms, including that on social security."