To provide a reproduction repeater using a bistable semiconductor laser capable of realizing a simple structure and high speed by performing direct reproduction repeating for every optical type without converting an optical signal into an electric signal.

The repeater is provided with a clock extracting circuit 12 and a bistable semiconductor laser 5 for performing an AND gate operation and a memory operation, and performs direct reproduction repeating for every optical type without converting an optical signal into an electric signal. The circuit 12 is provided with, for example, a first clock extracting section consisting of an external resonator 7 consisting of a semiconductor laser 5 having an AR coating 5A on its one side and a reflection mirror 6, and a second clock extracting section branching from the first section and having an optical delay means 13 and a wavelength plate 14. An input signal light 1, a first clock signal (0°) obtained from the first clock extracting section, and a second clock signal (90°) obtained from the second clock extracting section are inputted into the laser 5. The laser 5 has no time jitter by a 3R function and has a waveform and a peak value which are arranged in order, thereby obtaining coded reproduced output signal light.