An optimal value calculator calculates, based on angle information obtained from a first angle sensor provided in an ultrasound probe, the direction of transmission of an ultrasonic beam transmitted from the ultrasound probe, and the radiation source optimal angle of a radiation source at which the direction of radiation from the radiation source is substantially parallel to the calculated direction of transmission of the ultrasonic beam and the optimal detection angle of a radiographic image generator at which the normal of a detection surface of the radiographic image generator is substantially parallel to the calculated direction of transmission of the ultrasonic beam.
