The present invention provides a linear lighting device which includes an elongated light guide, a light source disposed at an end in a longitudinal direction of the light guide, and a case accommodating the light guide and the light source. In the linear lighting device, the light guide has a plurality of grooves arranged in the longitudinal direction of the light guide, and has a stepped cutout at the other end on an opposite side from the end, and a protruding portion protruding into the cutout is formed on an inner surface of the case which faces the cutout.