Patent ID: 8322898

Claim:
A bulb-type lamp comprising: a light emitting module including a substrate on which at least one light emitting element is mounted; a cylindrically-shaped heat sink that allows dissipation of heat therefrom, the heat being generated by the at least one light emitting element emitting light; a base member attached to one end portion of the heat sink; a mount member on a front surface of which the light emitting module is mounted, the mount member allowing conduction of the heat therefrom to the heat sink; and a circuit that is housed in the heat sink and, upon receiving power via the base member, causes the at least one light emitting element to emit the light, wherein the mount member allows conduction of the heat therefrom to the heat sink by being in contact with the other end portion of the heat sink, and a fraction S 1 /S 2 satisfies a relationship 0.5≦S 1 /S 2 ≦3.0 where S 1 denotes an area of a portion of the mount member that is in contact with the heat sink, and S 2 denotes an area of a portion of the mount member that is in contact with the substrate of the light emitting module.