A lighting device for use in vehicles includes a light generating part having a substrate and a light source disposed on the substrate; a base including a light emitting part having a light emitting surface for emitting light from the light source, and a reverse surface on a backside of the light emitting surface, and a connector housing part disposed on the reverse surface and housing a connector electrically connected to the light source; and a case assembled with the base and housing the light generating part and the connector housing part. The base including the light emitting part and the connector housing part is an integral molding and constituted by a light transmitting member containing a light diffusing material.