To provide an optical communication system that can realize prevention of an optical beat noise and improvement of signal quality at a low cost thereby increasing the number of signals that can be multiplexed from transmission stations and be applied to all electric modulation signals independently of whether or not a modulation component exists in the amplitude of the signal.

This invention of the optical communication system where the transmission stations 1A, 1B,..., 1N convert electric modulation signals with different subcarrier frequencies fa, fb,..., fn into optical signals, the optical signals from each transmission station are multiplexed into a signal that is sent through an optical fiber 4 to a reception station 5, is characterized in that an optical switch 3 is used to sequentially switch the optical signals from the transmission stations 1A, 1B,..., 1N to sample the optical signals into optical pulses, the optical pulse signals are multiplexed in a way of not being overlapped on a time base, the multiplexed signals are transmitted through the optical fiber 4 to the reception station 5, and the reception station uses a single photoelectric converter (optical detector) to detect them altogether.