PROBLEM TO BE SOLVED: To provide an improved technology for forming an ultrasonic image with an arbitrary cross section.SOLUTION: A cross section setting part 40 sets an arbitrary cross section by changing at least one of the position and direction of a cross section based on a tomographic image. The cross section setting part 40 sets the arbitrary cross section in a three-dimensional region by moving the cross section or changing inclination of the cross section in accordance with a user operation received from a user via an operation device 42. A transmission and reception control part 50 controls a transmission and reception part 12 so as to obtain a reception signal from the arbitrary cross section with transmission and reception processing specialized for the arbitrary cross section set by the cross section setting part 40.
