Actuator

An actuator (10) includes a lower housing member (20), an upper housing member (30) attached to the lower one, and a cover member. Inside thelower housing member are arranged a driving source (15), a power-transmitting mechanism (17) configured for transmitting a driving power of the driving source to a output shaft (18) to which a member to be driven is to be attached, a connector (21) having terminals (21a) projected therefrom. A partition plate (35) is provided in the upper housing member (30) and has an opening (39a,39b,39c) for exposing said terminals (21a) of the connector and adapted to define a partition chamber (38) opened to outside. A circuit board (40) is placed on the partition plate (35), and has connection terminals connected to the terminals of the connector with a solder on the partition plate. A control circuit is assembled into the circuit board for the driving source. The cover member (50) covers the circuit board.