Incandescent light-bulb socket of the type structured to support a light-bulb provided with a glass bulb housing the incandescent filament, and a connection plug which is arranged to close the neck of the glass bulb, and is structured so as to be fitted in the light-bulb socket; said connection plug being provided with an headpiece which houses the terminals of the rheophores that conduct the electric current to the filament, and with a peripheral flange that protrudes from the body of the plug, between the neck of the glass bulb and the headpiece of the plug; the incandescent light-bulb socket comprising: - a supporting platform which is provided with a coupling seat shaped so as to house/ accommodate the portion of the plug beneath the peripheral flange; - electric connection means located on the bottom of the coupling seat, and structured so as to contact the plug headpiece at the terminals of the reophores, when the plug is completely inserted in the coupling seat; and - a light-bulb retaining member which is located on the supporting platform, substantially at the mouth of the coupling seat, and is structured so as to hook the plug peripheral flange to prevent the subsequent extraction of the plug from the coupling seat, and so as to continuously exert, on the peripheral flange of the plug that engages the coupling seat, an elastic traction force directed towards the bottom of the coupling seat; the incandescent light-bulb socket being characterized in that said light-bulb retaining member comprises two or more flexible locking tongues which are appropriately distributed about the mouth of the coupling seat, and protrude from the supporting platform so as to form a projecting crown that towers above the mouth of the coupling seat; the distal ends of said tongues being profiled so as to form, on the top of the projecting crown, a converging and then diverging bottleneck, and having the possibility of reciprocally moving away so as to allow the bottleneck to elastically dilate so as to let the plug peripheral flange pass, and then to close back behind said peripheral flange for leaving in abutment against the peripheral edge of the plug peripheral flange the distal ends lower parts forming the divergent segment of the bottleneck; the distal end of at least one of the flexible locking tongues also being provided with at least one projecting stop tailpiece that protrudes from the tongue body towards the inside of the blottleneck, and is shaped so as to be fitted on the back/upper face of the peripheral flange of the plug that occupies the coupling seat, so as to prevent the reciprocal moving away of the distal ends of the tongues. - a supporting platform which is provided with a coupling seat shaped so as to house/ accommodate the portion of the plug beneath the peripheral flange; - electric connection means located on the bottom of the coupling seat, and structured so as to contact the plug headpiece at the terminals of the reophores, when the plug is completely inserted in the coupling seat; and - a light-bulb retaining member which is located on the supporting platform, substantially at the mouth of the coupling seat, and is structured so as to hook the plug peripheral flange to prevent the subsequent extraction of the plug from the coupling seat, and so as to continuously exert, on the peripheral flange of the plug that engages the coupling seat, an elastic traction force directed towards the bottom of the coupling seat;