The 17-year-old boy, who was the club's captain, was found by his mother hanging in his room on Dec. 23, a day after other members of the club said the coach slapped him during a practice game, The Yomiuri Shimbun reported Thursday.
The boy's death spurred an inquiry by the Osaka City Board of Education, which revealed its findings Tuesday.
The board said 22 boys and girls saw the 47-year-old coach hit the boy several times during the practice, while 38 said they saw the coach physically punish the student in the days before the game.
Some 21 members of the team said they had been physically punished by the coach and 48 said they had seen the coach hit other members, usually by slapping, beating or kicking.
A previous investigation was launched by the board in 2011 after a caller reported that a "male teacher in charge of the basketball club" was giving corporal punishment to students, the board said.
The school principal interviewed 13 teachers who ran sports clubs, all of whom said they did not use corporal punishment. No students were interviewed.