A catheter includes an outer tube, and an inner tube which is disposed inside the outer tube and through which a guide wire is passed via a distal-side opening and a proximal-side opening. The outer tube has, in the axial direction thereof, at least: a first region on the distal side； a second region disposed on the proximal side and higher in rigidity than the first region； and a transition region which is provided between the first region and the second region and of which rigidity varies from the same rigidity as that of the first rigidity to the same rigidity as that of the second rigidity. The outer tube is configured with an opening, to which the proximal-side opening of the inner tube is connected, being provided in the second region.
