To provide technology, with which the field of vision can be changed without moving a coupler for puncture in relation to the body and an ultrasonic probe and the coupler for puncture can be separated from the body while puncturing a puncture needle into the body.

In the ultrasonic diagnostic device provided with the coupler for puncture mounted between the body and the ultrasonic probe so that the ultrasonic probe can be moved to a prescribed position, an ultrasonic probe position detecting means for detecting the moving position of the ultrasonic probe and a means for moving and displaying a puncture guideline with the detected moving position, the coupler for puncture is equipped with a through hole groove for passing the puncture needle.