PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic device which can shorten the time for changing over to lower voltage when changing voltage transmitted to an ultrasonic probe over from high voltage to lower voltage.SOLUTION: An ultrasonic diagnostic device 1 configured so as to be connectable with an ultrasonic probe 2 comprises: a transmission part 4 which controls supply of a transmission electric signal for transmitting an ultrasonic wave to a subject from the ultrasonic probe 2； a reception part 5 which acquires a reception signal on the basis of a reflection ultrasonic wave received by the ultrasonic probe 2； a transmission voltage generation part 11 which supplies voltage to the transmission part 4； and a control part 7. The transmission voltage generation part 11 is connected to a ground potential via a switch 9 whose electrical connection is controlled by the control part 7. The control part 7 electrically connects the transmission voltage generation part 11 and the ground potential by turning the switch into the on-state until predetermined time elapses, and cuts off the electrical connection between the transmission voltage generation part 11 and the ground potential by turning the switch into the off-state after the predetermined time elapses.
