To surely waterproof the junction between a plate section or enclosure made of a synthetic resin and a metallic heat sink so that no gap nor crack occurs in the junction.

An enclosure 14 housing electronic equipment 12 is constituted of an upper case 16 and a lower case 18 made of a synthetic resin. An opening 1811 made through the bottom plate 101 of the lower case 18 is blocked with a metallic heat sink 20. A shrinkage stress absorbing section 22 which absorbs the shrinkage stress of the lower case 18 is provided on the whole outer periphery of the heat sink 209, namely, at the portion of the lower case 18 which is positioned on the whole outer periphery of the junction between the heat sink 20 and the opening 1811.