This device comprises: a casing (3), in which a plurality of conductive tracks are fixed, an operation element (5) which is arranged so as to be able to move in translation in the casing (3), a conductive dome-like member (51) which is arranged in the casing (3) and which is resiliently deformable under the action of the displacement of the operation element (5) between a first state and a secondstate of commutation, a light source (13) and at least two power supply tracks for the light source (13). The light source (13) is fixedly joined to the operation element (5), the operation element being provided with at least two contact elements (87) which connect, over the entire axial travel of the operation element (5) in the casing (3), the light source (13) to the respective power supply tracks.