A housing structure for vehicle-mounted electronic equipment according to the present invention is superior in heat dissipation, water resistance, heat resistance and vibration resistance. An electronic substrate is temporarily fixed onto an annular circumferential wall part of a cover made of fire retardant resin, and connector contact pins are soldered to the electronic substrate. The electronic substrate is fixed and held between a heat-transfer base and the annular circumferential wall part with screws, and heat generated by a heating part on the electronic substrate is transferred to the base and dissipated. The annular circumferential wall part has an annular groove in which a sealant is inserted, and the base has an annular protrusion snapped into the annular groove.