Provided is a transmission system capable of improving the SN ratio for noise superimposed on a transmission line and extending the dynamic range. The transmission system transmits a signal between a transmitter (1) and a receiver (3), which are connected to each other via a transmission line (2). The transmitter (1) includes a transmission amplifier (11) for stepping up an amplitude of an input signal. The receiver (3) includes: an amplitude comparison circuit (31) for attenuating the amplitude of the signal, which is output from the transmission amplifier (11) and input via the transmission line (2), and comparing the attenuated amplitude and a reference voltage; a variable attenuation circuit (32) for outputting, when the attenuated amplitude is larger than the reference voltage, the signal input to the receiver (3) after attenuating the amplitude of the signal, and for outputting, when the attenuated amplitude is smaller than the reference voltage, the signal input to the receiver (3) without attenuating the amplitude of the signal; and an amplitude limiting circuit (33) for clipping the amplitude of the signal output from the variable attenuation circuit (32) at a threshold voltage.