Abstract: An optical switch for switching an optical path includes a fixed reflection element disposed at each of crossing points of a plurality of lines and a plurality of redundant lines for switching the optical path to one of the redundant lines, and a movable optical unit disposed at each of the crossing points and including an optical path parallel move element. The optical path parallel move element has parallel surfaces for moving the optical path in parallel toward the fixed reflection element. The movable optical unit located on the optical path of one of collimators moves in and out the optical path incident from an auxiliary collimator to switch the optical path when the one of the collimators has a problem.