A lighting device includes an elongated profiled body with a web wall having first and second opposing faces, and two side walls to the side of the web wall, the latter having longitudinal slots extending therealong. In the profiled body, there may be provided an elongated light radiation source module including a support board with electrically conductive formations facing said longitudinal slots and at least one electrically-powered light radiation source which is in electrical contact with said electrically conductive formations. The light radiation source module is locatable in elongated profiled body extending between both side walls, with support board facing towards the first face of web wall. An electrical contact slider member slidable along the second face of web wall is provided with electrical contact pins adapted to extend into said longitudinal slots. Slider member is displaceable towards support board with pins contacting said electrically conductive formations of support board.