The light guide substrate 2 has mirror receiving grooves 24 and light guides. The light guides conduct light that is input into the input ports to selected output ports in accordance with the advance and retraction of the mirrors 31 with respect to the grooves 24. The actuator substrate 4 has mirrors 31 and actuators which place the mirrors 31 in a state in which the mirrors are drawn in toward the substrate 4, or a state in which the mirrors protrude from the substrate 4. The light guide substrate 2 and actuator substrate 4 are aligned using alignment marks and joined with a spacer 3 interposed so that the mirrors 31 retract from the grooves 24 when the mirrors 31 are drawn in toward the substrate 4, and so that the mirrors 31 advance into the grooves 24 when the mirrors 31 protrude from the substrate 4. This alignment is performed in a state in which all of the mirrors 31 are drawn in toward the substrate 4.