In an endless belt type grinding tool, a tension bar includes a front portion and a rear portion which are divided from each other in a tubular holding portion. The front portion and the rear portion forcibly abut against each other when the endless grinding belt wound around the drive pulley and the idle pulley is applied with a tension by the spring. The endless belt type grinding tool includes a locking member which, when the tension bar is pushed into the tubular holding portion against the spring, engages with the rear portion of the tension bar to retain the rear portion at the pushed position against the urging force of the spring. Thus, in a state in which the grinding belt is removed, it is possible to reduce damage even if the tension bar, which is being pushed in, accidentally jumps out.