Endoscopes comprise image pickup elements for picking up images and transmission circuits and the like for transmitting the picked up images with radio waves of different frequencies. In addition, bar codes to code the frequencies used for transmission are provided to the respective endoscopes, the bar code provided to the endoscope used in endoscope inspection is read on a receiver side, and a reception frequency of a station selection unit is set to the read frequency, so that a signal obtained by a desired endoscope can be easily received and imaged even in case a plurality of endoscopes are used.