An endoscope system 1 according to the present invention includes: an imaging sensor 25a； a clock signal generation unit 32 configured to generate and output a clock signal； a differential converter 33 configured to convert the clock signal into a differential signal； a pair of differential signal cables 26 that is a pair of signal lines configured to supply the clock signal as the differential signal and configured such that impedance matching does not occur at a terminal of one signal cable 26b； and an adjustment unit 37 configured to send a detecting signal to the signal cable 26b and to adjust at least characteristics of the clock signal generated by the clock signal generation unit 32 based on a time period from when the detecting signal is sent until the detecting signal is reflected and returned from the terminal of the signal cable 26b.
