An electronic control apparatus can be reduced in size and cost by eliminating certain parts such as a power board, etc. The apparatus includes a housing, a heat sink attached to one end of the housing, semiconductor switching elements mounted on the heat sink, a circuit board arranged in opposition to the heat sink, and a plurality of conductive plates electrically connecting the circuit board and the semiconductor switching elements. The heat sink is composed of a heat sink main body, and an anodized aluminum film formed at least on a surface of the heat sink main body at a side at which the power device is mounted thereon, and the heat sink main body has outer peripheral end faces arranged in opposition to inner wall surfaces of an opening portion of the housing.