An endoscope system includes: a CMOS image pickup device configured to output digital signals of a plurality of systems E/O converters configured to convert the digital signals of the plurality of systems to optical signals respectively optical fibers configured to transmit the optical signals of the plurality of systems respectively a transmission amount changer configured to convert a data amount of the digital signal of at least one system and a metal wire configured to transmit the digital signal, the data amount of which is converted by the transmission amount changer.
