A radiotherapy apparatus control method according to the present invention includes: a step S6 of calculating rotational and first translational correction amounts based on a position and orientation of a first region represented by a radioscopic image of a subject and a step S9 of calculating a second translational correction amount based on a position and orientation of the second region represented by the radioscopic image and the rotational correction amount and a step S10 of driving a couch so that it rotates by the rotational correction amount and translates by the second translational correction amount. The first region is larger than the second region. According to such a method, the second region can be arranged in a predetermined position at higher accuracy compared with a case where the position of the couch is adjusted by using the position and orientation of only one of the first and second regions.
