Particle beam therapy apparatus and control method thereof

A particle beam therapy apparatus has a position and posture setter that moves a movable body, that is at least one of the irradiation nozzle and the treatment table. A movement path of the movable body is determined when adapting the positional posture of the movable body from one condition among a plurality of prescribed conditions to another condition. An evaluation value is obtained for adapting the positional posture of the movable body to each of a plurality of prescribed conditions. This evaluation value is for a case of moving the movable body according to the movement path. A setting order is determined for adapting the positional posture of the movable body to each prescribed condition based on the evaluation value; and the positional posture of the movable body is adapted to each of the plurality of prescribed conditions by moving the movable body according to the determined movement path.