PURPOSE: To provide an optical switch for distributing plural light signals to plural subscribers.

CONSTITUTION: An optical path for propagating plural light information signals intersects with an optical path for transmitting the light to the plural subscribers. An optical branching part 20 for branching the requested light information signals is arranged at the intersection point. The loss by branching of the light information signal is compensated by optical amplification, thereby the signals are distributed to all the subscribers while the specified intensity is maintained. The same light signals are distributed to the plural subscribers. The expansion in correspondence to an increase in the number of the light information signals and the number of the subscribers is easy.