PROBLEM TO BE SOLVED: To allow calculation of delay time for each vibration element to be easily performed.SOLUTION: An ultrasonic diagnostic device includes an ultrasonic probe, a delay time calculation part, a transmission and reception part, and an image generation part. The delay time calculation part calculates delay time required for transmission and reception of an ultrasonic wave in a representative coordinate in a sub array or in the vicinity thereof for each sub array obtained by dividing the arrangement of a plurality of vibration elements of the ultrasonic probe, and calculates delay time in each vibration element with approximation on the basis of the delay time and a difference of each vibration element contained in the sub array with respect to the representative coordinate. The transmission and reception part performs transmission and reception of the ultrasonic wave in the plurality of vibration elements of the ultrasonic probe with the delay time on the basis of the delay time calculated for each vibration element. The image generation part generates image data inside a subject from the ultrasonic wave received by the transmission and reception part.
