Disclosed is a treatment device for an endoscope including a treatment part that is adapted to treat tissue within a body cavity, a manipulating part that is adapted to manipulate the treatment part, a manipulation shaft member that connects the treatment part and the manipulating part, a multi-wire coil sheath that is formed by spirally winding a wire bundle having a plurality of element wires arranged in a longitudinal direction, and a plurality of fixing portions that is arranged between a distal end and a proximal end of the multi-wire coil sheath and restricts a first relative movement between the plurality of element wires and a second relative movement between parts of the wire bundle that are adjacent to each other as being spirally wound. The manipulation shaft member is inserted into the multi-wire coil sheath so that the manipulation shaft member is capable of being advanced and retracted.