A semiconductor light emitting device has an outer lead disposed along an outer wall of a mold resin portion perpendicular to a light-emitting plane of a light emitting diode. An outer lead is also disposed at an outer wall of the mold resin portion parallel to and opposite to the light-emitting plane. The outer wall of the resin mold where the outer lead is disposed is taken as a mount face. Each outer wall of the mold resin portion constituting a mount face includes at least one outer lead for an anode and a cathode. According to the present configuration, there is provided a semiconductor light emitting device that allows selection of side-emission mounting or top-emission mounting with the same components on a mount substrate.