For the purpose of switching the liquid delivery mode in accordance with whether forceps are open or closed, an endoscopic surgical device (1) according to the present invention includes: a sheath (2) insertable into a channel of an endoscope and having a pipe (2a) capable of delivering a liquid； a forceps section (3) disposed so as to protrude from a distal end cover (30) provided at a distal end of the sheath (2) and including a pair of openable-closable forceps components (3a)； an operable member (4d) that is connected to a proximal end of the forceps section (3) and that opens the forceps components (3a) when the operable member (4d) is moved forward in a longitudinal direction and that closes the forceps components (3a) when the operable member (4d) is moved rearward； and a flow-path formation member (7) that has a through-hole (7a) through which the operable member (4d) extends and that has a first liquid delivery hole (9) constituted by a gap between the through-hole (7a) and the operable member (4d) and a second liquid delivery hole (8) constituted by a gap between the flow-path formation member (7) and an inner peripheral surface of the distal end cover (30). The operable member (4d) is provided with a large-diameter section that abuts on the flow-path formation member (7) when the operable member (4d) is moved forward so as to block the first liquid delivery hole (9).
