An endoscope 2 has a CCD 9 incorporated in the distal part of an insertion unit 6 thereof. The sensitivity of the CCD 9 can be varied by applying a plurality of pulsating driving signals so as to change an electron multiplication rate. The endoscope 2 is connected to a processor 3 so that it can be disconnected freely. Information representing a type of endoscope stored in advance in a ROM 48 is transmitted to a controller 21 incorporated in the processor 3. The control means 21 uses a CCD sensitivity control means 12 to control the sensitivity of the CCD 9 according to the type of connected endoscope 2. Consequently, a view image of proper brightness can be produced irrespective of the type of endoscope 2.