A light signal switching apparatus has an input port and output ports, and outputs an output light from a desired output port. The apparatus has a splitter polarizing an input light into first and second polarized light whose polarization planes are different mutually by 90 degrees, a first polarization controller rotating a polarization plane of the second polarized light by 90 degrees to output a third polarized light, a first optical switch switching a path of the first polarized light to the desired output port side, a second optical switch switching a path of the third polarized light to the desired output port side, a second polarization controller rotating a polarization plane of the first polarized light by 90 degrees to output a fourth polarized light, and a combiner combining the third polarized light with the fourth polarized light, to output a combined light to the desired output port.