The invention discloses an optical selector switch and a signal-processing apparatus. An optical selector switch contains an optical waveguide that includes a first optical waveguide portion having a first light-transmissivity, a second optical waveguide portion having a second light-transmissivity, reflecting members that reflect light, and a light-dividing device that reflects and transmits light; at least one light-emitting unit that emits the light toward the first optical waveguide portion of the optical waveguide; and at least one light-receiving unit that receives the light which is incident to the first optical waveguide portion of the optical waveguide from the light-emitting unit, based on a directivity due to an angle of the incident light to the first optical waveguide portionof the optical waveguide, wherein the incident light to the first optical waveguide portion is emitted radially toward the circumference of the second optical waveguide portion of the optical waveguide.