To provide an ultrasonic diagnostic device capable of preventing difficulty of seeing a picture image due to noise caused by a radio knife.

The ultrasonic diagnostic device 1 is constituted of a probe (measuring part) 2 to which the radio knife 10 is connected through a connector 8 free to connect and disconnect and to mainly transmit and receive an ultrasonic wave to and from a subject, a transceiver means 3 (transceiver circuit 31 and pulse generator 32) to oscillate the ultrasonic wave by driving the probe 2 and to encode and process a received echo, a device control part (control means) 4 to intermittently (periodically) transmit and receive the ultrasonic wave by driving the probe 2 and to control the electric knife 10 not to work during a period of transmitting and receiving the ultrasonic wave, a working switch 5, a DSC (picture image signal conversion part) 6 to convert a processed signal by the transceiver means 3 of the echo to a picture image signal and a monitor (picture image display part) 7 to display the picture image signal as the picture image.