The present disclosures provides an electronic control apparatus for a vehicle using overmolding in which a heat radiating plate is attached to an opposite side of a part requiring heat radiation in a printed circuit board (PCB) and a part other than the part, to which the heat radiating plate is attached, is overmolded so as to directly discharge heat to the air through the heat radiating plate such that a heat radiation effect is excellent, the heat radiating plate is attached in advance and then a housing is formed of mold resin such that a manufacturing process is simplified, and a printed circuit board (PCB) is surrounded by mold resin such that a waterproof function is excellent, and a manufacturing method thereof.