A surgical instrument includes: a fluid chamber to which fluid is supplied a pulsation generator which produces pulsed flow by pressurizing the fluid supplied to the fluid chamber an outlet channel which communicates with the fluid chamber through which the pulsed flow is transmitted a fluid ejection opening which communicates with the outlet channel through which pulse flow is ejected toward an ejection target a suction opening provided in the vicinity of the fluid ejection opening and a fluid suctioning unit which suctions the fluid through the suction opening, wherein the opening area at an outlet opening end of the fluid ejection opening on the side near the ejection target is larger than the opening area at an inlet opening end of the fluid ejection opening on the side near the outlet channel.
