A treatment device includes: an operating section; an elongated insertion section connected to the operating section; a pair of clamp members provided at the distal end of the insertion section so as to be openable and closable relative to each other; a movable member that is moved so as to push staples relative to tissue sandwiched between the clamp members; and a coil member that is arranged so as to pass through the insertion section in the longitudinal direction and that transmits a pressing force from the operating section to the movable member.