TOKYO - Japan's parliament installed Naoto Kan as the new prime minister Friday, handing the outspoken populist the job of rallying his party and reclaiming its mandate for change ahead of elections next month. Kan, a 63-year-old veteran with a reputation for confronting Japan's powerful bureaucrats, succeeds Yukio Hatoyama, who stepped down Wednesday after squandering the public's high hopes with broken campaign promises and financial scandals. "My task is to rebuild this nation," said Kan, who served as Hatoyama's finance minister. He must now contend with a daunting list of problems. The world's No. 2 economy is burdened with the largest public debt in the industrialized world, sluggish growth and an aging, shrinking population. But more urgently, with upper house elections looming in July, he will need to convince voters of his party's competence after they were disappointed by Hatoyama's financial scandals and bungled handling of the relocation of a U.S. Marine base in Okinawa. Kan's first task will be to form a Cabinet, which the Prime Minister's Office suggested would not happen until next week. "We will work together as one in the face of the tough political situation and the upcoming upper house elections and fight together unified," he said to party members. "Our first priority is to regain the trust of the people." Kan, the country's sixth prime minister in four years, pledged to confront problems linking money and politics. He also stressed the need for fiscal discipline while trying to spur economic growth. Chosen Friday morning as new chief of the Democratic Party of Japan, Kan was voted into office a few hours later by the lower house, the more powerful chamber of Japan's parliament. Kan received 313 votes out of 477, with Liberal Democratic Party head Sadakazu Tanigaki getting 116. The rest went to other candidates of smaller parties. The upper house approved Kan immediately afterward. While his political philosophy is hard to neatly categorize, analysts and fellow lawmakers agree that his personal traits and background as a civic activist and proactive Cabinet minister set him apart from Hatoyama. "He has a record of acting on the basis of his beliefs and not backing down," said Tobias Harris, a political analyst who once worked as an aide to a Democratic lawmaker in Japan. "Those are good signs for a prime minister, and I think those are qualities that Hatoyama did not have." With his ordinary upbringing, Kan represents a break with the past several prime ministers, including Hatoyama, whose fathers or grandfathers served as prime ministers. The son of a businessman, Kan graduated from the Tokyo Institute of Technology's science department. He began his political career as a civic activist in the 1970s and ran for office three times before winning a lower house seat in 1980 with the now-defunct Socialist Democratic Federation.