In one embodiment, a lamp (10) includes a thermal conductive hollow base body (13) having a concave container portion (13c), an opening portion (13a) formed at one end portion so as to communicate with the container portion (13c) and a substrate support portion (13e) formed at a peripheral portion of the opening portion (13a). A substrate (14) is formed of one of a thermal conductive metal plate and a thermal conductive insulating plate and including a semiconductor lighting element (11) mounted on one surface (14a) of the substrate (14). A peripheral portion of the other surface (14e) of the substrate (11) is fixed to the substrate support portion (13e) so as to cover the opening portion (13a) in a thermally conductive state therebetween. A power supply device (12) is accommodated in the container portion (13c) of the base body (13) to light on the semiconductor lighting element (11). A base (17) is provided at the other end portion side of the base body (13) and electrically connected with the power supply device (12).