Calls had been rising within his Democratic Party for him to step aside before elections on July 11 that are seen as a referendum on the party’s first year in power.

Image Prime Minister Yukio Hatoyama of Japan bowed before his party’s lawmakers at the national Diet in Toyko on Wednesday. Credit... Yoshikazu Tsuno/Agence France-Presse — Getty Images

“Unfortunately, the politics of the ruling party did not find reflection in the hearts of the people,” Mr. Hatoyama told an emergency meeting of Democratic lawmakers, broadcast live on television. “It is regrettable that the people were gradually unwilling to listen to us.”

Mr. Hatoyama is the fourth Japanese prime minister to resign in four years, which is likely to renew soul-searching about Japan’s inability to produce an effective leader and to feed concerns that political paralysis is preventing Japan from reversing a nearly two-decade-long economic decline. Mr. Hatoyama, who was teary-eyed as he announced his departure, was also following the common Japanese practice of leaders’ resigning to take responsibility for failure.

His resignation will not force a change in government, because the Democrats still hold a commanding majority in Parliament’s Lower House, which chooses the prime minister. But it will be a damaging blow to a party that had taken power in a landslide election victory that ended more than a half-century of nearly unbroken one-party control.

Mr. Hatoyama took power with vows to challenge the bureaucracy’s grip on postwar governing and revive Japan’s economy. Instead, his inexperienced government appeared to become consumed by the issue of the Okinawa base and a series of investigations into the political financing of Mr. Hatoyama and his backer in the party, Ichiro Ozawa.