There is disclosed in DE-B-38 03 212 (U.S. Pat. No. 4,881,523) an endoscope for nasal surgery having an outer endoscope shaft comprising a suction and flushing shaft and a handle connected to the outer shaft, a switching valve being provided in the handle for connecting the suction and flushing shaft to, and disconnecting it from, a source of negative pressure and a flushing fluid source. An optical system extends centrally through the endoscope shaft, so that a further shaft for receiving a surgical instrument cannot be provided.