This treatment instrument for endoscope includes a sheath that is capable of being inserted into a treatment instrument channel of an endoscope, a treatment part provided on a distal-end side of the sheath, a first wire that is connected to the treatment part and inserted into the sheath, the first wire including a first core member and a first covering member that covers the first core member, and a second wire that drives the treatment part, connected to the treatment part and inserted into the sheath so that the second wire is capable of moving relatively with the first wire in a state where an outer peripheral surface of the second wire capable of contacting the first wire, the second wire including a second core member and a second covering member having a different surface condition from that of the first covering member.
