A treatment device (1) includes: an operating section (3)； an elongated insertion section (2) connected to the operating section (3)； a pair of clamp members (5 and 6) provided at the distal end of the insertion section (2) so as to be openable and closable relative to each other； a cutter provided in one clamp member (5)； a movable member that is moved so as to push the cutter relative to tissue； and a driving mechanism for moving the movable member towards the distal end side. The driving mechanism includes: a coil member arranged so as to pass through the insertion section (2) in the longitudinal direction and transmits a pressing force from the operating section (3) to the movable member； and a guide wire both ends of which are fixed to the one clamp member (5) and to the operating section (3).
