Positioning of an ultrasonic image and volume data captured in advance is performed accurately without requiring a complicated operation from the user. The first volume data of the ultrasonic image and the second volume data obtained by another image capturing device are received and aligned. The selection of a predetermined imaging part among a plurality of imaging parts of the subject is received from the user. The second volume data is initially rotated by the rotation angle corresponding to the imaging region received by the receiving unit, and the second volume data and the first volume data after the initial rotation are further aligned.超音波画像と、予め撮像したボリュームデータとの位置合わせを、ユーザに煩雑な操作を要求することなく、正確に行う。 超音波画像の第１ボリュームデータと、別の画像撮像装置が得た第２ボリュームデータを受け取って位置合わせする。被検体の複数の撮像部位のうち所定の撮像部位の選択をユーザから受け付ける。受け付け部が受け付けた撮像部位に応じた回転角度だけ、第２ボリュームデータを初期回転させ、初期回転後の第２ボリュームデータと第１ボリュームデータとをさらに位置合わせする。
