In a vehicle control unit structure, a pair of first and second circuit boards in each of which conductive layers are adhered on a metal substrate through an insulating layer, and a circuit element is fixed to each of the conductive layers are arranged so that the conductive layers are connected to each other through a connecting substrate and are arranged to oppose each other. A third circuit board is located between the first and second circuit boards. The foregoing vehicle control unit structure is arranged into a closed case-like shape, thus preventing dust contamination and direct access by an operator and achieving a low cost, compact unit. A circuit element is mounted on the third circuit board.
