A signal receiver which receives an optical signal from a remote control includes a light guide for guiding a light passing through a front panel window toward a photodetector mounted on a circuit board. The light guide is made of a homogeneous material. A light guiding portion of the light guide extending from an entrance end to an exit end has a substantially circular cross section and is curved gently, not angularly. The exit end is configured to have a concave surface which is coaxial with the axes of both the cross section of the light guiding portion and a light-receptive portion of the photodetector. The exit end is disposed adjacent and opposite to the light-receptive portion.