A movable member (30) provided in a housing (10) is formed with a cover (32) configured to cover inserting edges (45) on a tip of a circuit board (41) in an inserting direction into a board accommodation space (15) when the circuit board (41) is inserted into the board accommodation space (15) and a receiving surface (34) configured to move the movable member (30) integrally with the circuit board (41) to a back side of the board accommodation space (15) by being pushed by the circuit board (41). The movable member (30) and the circuit board (41) are formed with locks (38, 46) configured to move the movable member (30) integrally with the circuit board (41) in a withdrawing direction from the board accommodation space (15) by locking each other.