A robot system includes: a robot arm; a robot hand provided on the robot arm; a contact unit provided on the robot hand for rotating a rotation body of a rotation device which includes the rotation body capable of housing a work and a fixed part rotatably supporting the rotation body and which performs a predetermined process on the work; a detection unit configured to detect a detection target part provided on the rotation body; and a first control unit configured to control operation of the robot arm and the robot hand so that the contact unit rotates the rotation body up to a predetermined rotational position according to a result of detecting the detection target part by the detection unit.