Automotive power conversion device

Without using a special shielding member, it can shield the circuit unit, to obtain a vehicle power conversion device for can achieve cost reduction and size reduction. A conductive housing is opened, and a multilayer printed wiring board is one layer GND plane is implemented circuit portion, the assembling of the multilayer printed wiring board to an opening surface of the opening of the conductive housing closed to form a space, said electrically be connected to the conductive housing the GND plane of the multilayer printed wiring board is housed in the conductive housing and the multilayer printed wiring board with enclosed within said closed space shielding the circuit portions.