Provided is an ultrasonic treatment device capable of shortening operating time even when excision/hemostasis is performed at a plurality of locations. The ultrasonic treatment device is provided with: a probe which is inserted into a sheath; and a treatment section which is linked to or formed as a single unit with the tip end section of the probe and is exposed outside of the sheath, and the ultrasonic treatment device transmits ultrasonic waves to the treatment section by way of the probe to excise or clot an affected area, the ultrasonic treatment being characterized in being provided with a mechanism for cooling the treatment section by subjecting the probe to heat exchange with a cooling gas that is discharged into the sheath.