A generating unit generates a plurality of ultrasonic cross-sectional images at a plurality of angles when an ultrasonic wave emitting surface in an ultrasonic probe is rotated. A regenerating unit saves information on the angle of the ultrasonic wave emitting surface when a predetermined condition is satisfied, and rotates the ultrasonic wave emitting surface from the angle of the ultrasonic wave emitting surface different from the saved angle information to the angle based on the saved angle information.