A treatment instrument apparatus, which is an endoscopic treatment instrument, includes a sheath having an opening in a distal end an actuator placed in the sheath and driven by a gas supplied via a tube a treatment unit connected with the actuator by a wire and placed on a distal end side of the opening of the sheath and an opening and closing switch, which is an operation portion used for an operation of supplying the gas into the sheath and supplying the gas to the actuator.
