An aim of the invention is to increase vibration resistance of a connection terminal (23), a tip of which is soldered to a circuit board (13). In a controller, the circuit board (13) is accommodated in a controller housing (6) made of metal, and the tip of the connection terminal (23) that extends from an actuator housing through an opening (24) is fixed to the circuit board (13). Semiconductor switching elements (27) and electrolytic capacitors (28) as heat generating components are collectively arranged in an area of the circuit board adjacent to the connection terminal (23), and the circuit board (13) is adhered and fixed to a top surface (30a) of a heat mass via a thermal conductive adhesive (31). At the same time as that heat dissipation is improved by the thermal conductive adhesive (31), a load caused by vibration is reduced because the circuit board (13) is fixed at a position near the connection terminal (23) to the controller housing (6).