To prevent inferior connection and breaking of connecting pins by electrically connecting a scope to an external device by the minimum number of the connecting pins.

An image signal and a control signal are converted into radio frequencies of a radio transmission system and a cable transmission is performed using the radio frequencies via a single coaxial cable 33 provided between the scope 10 and a processor 12. An electromagnetic coupling means comprising a primary coil 24a and a secondary coil 24b is provided between a connector 10C and a light source device 11 and the power is supplied to the scope by electromagnetic induction. This constitution can connect the scope 10 to the processor 12 and to the light source device 11 by two wires alone including an earth wire.