Patent ID: 8670234

Claim:
An electronic control device for controlling an electric actuator, comprising: a casing fixable to an actuator housing of the electric actuator; a circuit board accommodated in the casing, on which electronic parts including a heat generating part are installed; a projecting portion projecting from an inside surface of the casing, a region of the circuit board in which the heat generating part is installed being seated on the projecting portion; an air passage formed between the inside surface of the casing, the circuit board and an outer peripheral surface of the projecting portion; a vent hole extending through the casing to communicate the air passage and an outside of the casing with each other; and a communication hole extending through the casing such that when the casing is fixed to the actuator housing, an inside space of the actuator housing and the air passage are communicated with each other through the communication hole, wherein the air passage allows air to flow between the vent hole and the communication hole when the electric actuator is driven in a state that the casing is fixed to the actuator housing.