A surgical apparatus 20 includes a distal end opening portion (127) which id provided at the distal end portion of a sheath unit (60) to allow the liquid which has flowed through a water supply channel (125) to flow out, a treatment portion (70) which is provided at the distal end portion of an ultrasonic probe (51) to protrude outward from the distal end opening portion (127) and which treats a treatment part (200) with the ultrasonic vibrations. The treatment portion (70) includes a treatment region (70c) which treats the treatment part (200) with a liquid which has flowed out from a distal end opening portion (127) and with ultrasonic vibrations while the treatment region (70c) is in abutment with the treatment part (200) and a hydrophilic region (75a) which is formed by the application of a hydrophilic coat and which is provided in part of the circumferential surface of the treatment portion (70) to be provided from the treatment region (70c) to an end portion of the treatment portion (70) located in the distal end opening portion (127).
