PROBLEM TO BE SOLVED: To provide a catheter for an endoscope capable of not obstructing smooth operation of a treatment instrument body and also achieving smooth positional operation of a distal end.SOLUTION: A catheter for an endoscope includes: a main tube (22) provided with a main lumen (23) inside, which is capable of exposing and drawing the distal end (47) of a treatment instrument body (40) through an opening (24) at the distal end side and a guide wire tube (32), which has a fixed part (36) fixed to the distal end part of the main tube and having a length of 3-30 mm and a free part (38) extending from the fixed part to the proximal end side and not fixed to the main tube to be separable from the main tube and is provided with a guide wire lumen (33) inside capable of exposing and drawing the distal end (57) a guide wire 50 through an opening (34) at the distal end side.
