After struggling throughout his campaign, ex-Prime Minister Naoto Kan, a former leader of the Democratic Party of Japan, won the last seat in Sunday's national election, which saw candidates vying for the 475 seats in the Lower House.

Like the last election two years ago, Kan lost to his rival from the Liberal Democratic Party in his single-seat electoral district in Tokyo, but later won a seat through the proportional representation route. Under the election system, gaining a seat in a single-seat constituency means voters support the candidate.

"I am sorry that I didn't gain a seat in my district despite the tremendous support I received," Kan said in a news conference early Monday morning, making a small bow. "It is my responsibility that I couldn't win enough support."

Reports that Kan lost in the single-seat election district initially prompted supporters to express disbelief over his defeat. Kan had waited at home with his wife for the proportional representation results and appeared at his campaign office at around 3 a.m. on Monday.

"I'd like to do my best to realize my election pledge to stop nuclear energy and the dangerous Abe government," said Kan, an opponent to atomic power and a foe of Prime Minister Shinzo Abe's LDP-led ruling bloc. After shaking hands with the roughtly 10 supporters still in the office, he left without shouting banzai.

Kan started making speeches in his electoral district before the campaign date was officially announced. He stressed his opposition to nuclear power at the start of his campaign, apparently drawing little voter reaction. Then he changed his strategy and started to stress measures against the large number of suicides that he pursued when he was prime minister. But he struggled throughout his campaign. One voter yelled at him that nothing had improved even after voters gave his government, which was led by the Democratic Party of Japan, a chance.