A treatment portion includes a treatment region which treats a treatment part with a liquid which has flowed out from a distal end opening portion and with ultrasonic vibrations while the treatment region is in abutment with the treatment part. The treatment portion further includes a hydrophilic region which is formed by the application of a hydrophilic coat and which is provided in part of the circumferential surface of the treatment portion to be provided from the treatment region to an end portion of the treatment portion located in the distal end opening portion in a longitudinal axis direction.
