Provided is an inexpensive and highly reliable resin sealed-type onboard electronic control device is mounted in a vehicle such as an engine control unit and a control unit for automatic transmission, which have a heat dissipation structure for dissipating heat generated from an electronic component such as a semiconductor element. The onboard control device includes a circuit board, a member provided to face the circuit board, a heat generating electronic component mounted between the circuit board and the member, a heat dissipating material provided between the heat generating electronic component and the member, and a sealing resin to seal the circuit board and the heat generating electronic component. And a space between the member and the circuit board is at least a part of a range where the heat dissipating material is not provided, and is narrower than a range where the heat dissipating material is provided.