Naoki Tanaka, the husband of former Foreign Minister Makiko Tanaka, retained his seat in Sunday's House of Councilors election.
Tanaka, 64, was elected to his second term in the Upper House from the Niigata prefectural constituency. Makiko Tanaka represents the prefecture's No. 5 district as an independent member of the House of Representatives.
Tanaka, who assumed his wife's family name when they married, was elected to the Upper House for the first time in 1998 after serving three terms as a Lower House member from a district in Fukushima Prefecture.
His victory apparently stems partly from strong backing from his wife, a popular lawmaker in Niigata Prefecture, who went on campaign tours with him.
"People said I owe my wife for the victory," Tanaka said in a news conference. "I am grateful to her."
Tanaka and Masamichi Kondo, 57, an independent backed by the Democratic Party of Japan, were elected from the two-seat constituency. Tanaka received 367,059 votes, while Kondo got 428,117.
Tanaka retained his seat despite divisions within the prefectural chapter of the LDP, which fielded both Tanaka and Ichiro Tsukada, who garnered 319,968 votes.
Some LDP members in the prefecture have been unhappy with Tanaka, who supported his wife in the Nov. 9 House of Representatives election instead of an LDP candidate.
The outspoken Makiko Tanaka told reporters, "I think it is best to transfer power to the DPJ as soon as possible, considering the number of votes it won."
Although Makiko Tanaka is an independent lawmaker, she belongs to a Diet group formed mainly by the DPJ.