An electronic endoscope and a processor of an electronic endoscope apparatus transmit and receive signals via radio waves within a predetermined frequency band to which plural channels are allocated. The electronic endoscope has a transmission frequency band switching circuit which switches between a first and second transmission frequency bands, and a first channel detection circuit for detecting an available channel. The processor has a reception frequency band switching circuit which switches between a first and second reception frequency bands, and a second channel detection circuit for detecting an available channel. The transmission and reception frequency band switching circuits automatically switch the transmission and reception frequency bands according to detection results of the first and second channel detection circuits.