Fifteen members of the Kokushikan University soccer team were arrested Wednesday for allegedly sexually assaulting a minor in June, police said.
All 15 men have confessed to the crime.
Takashi Hamano and Satoshi Sasakawa, both 21, and the 13 others, aged between 18 and 21, were arrested for allegedly assaulting the girl, now 16, at Sasakawa's condominium in Machida, western Tokyo.
The acts are in violation of the Child Welfare Law and the Tokyo Metropolitan Government regulations on child welfare.
According to investigators, Hamano, a sophomore of the political science and economics department, met the high school girl in late May. He invited her to visit Sasakawa's condo on June 2, and also sent mobile phone messages to about 20 of his teammates that read: "A gift from Hamano. Assemble if you want to get laid with a high school girl."
At the condo, the 15 men spent about seven hours sexually assaulting the girl, the police said.
Police said they are looking into whether the men made similar attacks on other girls.
The soccer team is one of the strongest university teams, having won several tournaments. It is the only university team in the amateur Japan Football League.
Hideo Osawa, president of the university, said the soccer club's activities will be suspended.
Established in 1956, the team currently has about 240 members.
Kokushikan is a private university in Tokyo.