An endoscopic submucosal dissection device includes: a cap that is separably attached to a distal end of an insertion portion of an endoscope; a first holding portion and a second holding portion; a wire portion at least one part of which protrudes from the first holding portion and the second holding portion and is formed into a loop shape, and which is held by the first holding portion and the second holding portion to be movable forward and backward; an electrode portion that is provided at the part of the wire portion; an insulation member; and an operation portion that is connected to the wire portion and moves the electrode portion between the first holding portion and the second holding portion, wherein the first holding portion and the second holding portion are formed at opposite sides with a center axis of the cap being interposed therebetween.