Provided is a lamp designed to use as a light source a solid-state light emitting device with a simple and inexpensive structure and having an improved heat dissipation performance. A lamp uses a solid-state light emitting device as a light source. A cap is mounted to an external apparatus at the time of use. A housing is made of a translucent material and is connected to the cap. A light-emitting module includes one or a plurality of solid-state light emitting devices and is mounted such that the main-light-emission side (lower side in FIG. 1) thereof is in close contact with the inner wall of the housing. Further, the gap between the housing and the light-emitting module may be filled with a thermal conductive material having a translucency and a thermal conductivity.