In a disclosed method for inserting an endoscopic device, in a state in which a guide wire is inserted through an opening of a hollow organ of a subject, the guide wire is indwelt in the hollow organ. Next, a flexible endoscope is made to approach the opening of the hollow organ. Next, inside of the body of the subject, an endoscopic device that projects from the tip of a channel of the endoscope slidably engages with the guide wire. Next, the endoscopic device is inserted into the hollow organ through the opening, along the guide wire. The guide wire that is indwelt once is subsequently used as a guide for second and subsequent insertions of endoscopic devices.
