of the slider 51 to restrict the curvature of the tube 4 moreover the body member 50 is provided with a stopper pin 54 that extends across the guide hole 50 a and can abut against the slider 51 see fig1 if the slider 51 is manually advanced or retreated according to this configuration therefore the operating wire 13 is pushed or pulled and the distal end side of the tube 4 is bent in the up or down direction within a given range that is determined by means of the stopper pin 54 if the slider 51 is unhanded the slider 51 is held as it is and the bent state of the tube 4 can be maintained the following is a brief description of the way the catheter with the aforementioned configuration is endoscopically guided to for example a duodenal papilla as in the case shown in fig1 the insert section of the endoscope is first inserted into a region near the duodenal papilla and the insert section 2 of the catheter according to the present embodiment is then inserted into the channel of the insert section of the endoscope in inserting the insert section 2 of the catheter into the channel of the endoscope the insert section 2 is oriented in the rotating direction in advance so that the insert section 2 projects.