Abstract: An endoscopy device for introducing an expandable body into a cavity includes a first endoscope having a working channel, a further endoscope accommodating the expandable body and insertable with the expandable body in the working channel of the first endoscope, and a video unit located in the further endoscope in parallel relation to the expandable body and having a distal end situated next to a distal end of the expandable body in order to place the expandable body under visual control in the cavity prior to expansion. The video unit is designed to form an abutment at a proximal end of the expandable body after positioning of the expandable body and when the further endoscope is withdrawn.