A relay in which a relay body and a light source are incorporated in a case, the light source emitting light in conjunction with operation of the relay body, wherein a light guide is provided inside an outer surface of the case, the light guide is configured to take in the light emitted from the light source, to guide the light to a portion parallel to a top panel of the case, and to spread the light in the portion parallel to the top panel, and an optical pattern is provided in at least one of a top surface and a bottom surface of the portion parallel to the top panel, the optical pattern is configured to output, the light guided in the light guide to the portion parallel to the top panel, to outside the case from a top surface of the top panel.