A lighting device and a lighting fixture of the embodiment of the present invention comprises a thermally conductive main body having a substrate support portion in one end portion, and having a through-hole and a groove portion formed in the substrate support portion, the through-hole penetrating from the one end portion to the other end portion of the main body, the groove portion extending continuously from the through-hole, a substrate mounted with a semiconductor light-emitting device, and disposed on the substrate support portion, an electrical connector connected to the semiconductor light-emitting device, a power supply device housed in the main body and configured to light the semiconductor light-emitting device, a wire connected to the power supply device and to the electrical connector while being inserted through the through-hole and the groove portion, and a base member provided in the other end portion of the main body and connected to the power supply device. Therefore, a lighting device and a lighting fixture of this embodiment of the present invention reduced in size, is configured to be suitable for mass production and is capable of producing a certain luminous flux.