A connector is provided with a housing (10) to be connected with a mating connector housing (70) upon receiving a pushing force from behind, and a slider (40) (connection detecting member) to be mounted into the housing (10) relatively movably between a standby position and a connection position. The slider (40) includes such an operating plate (41) as to entirely cover the rear end surface of the housing (10) at a position behind the rear end surface of the connector housing (10). If the operating plate (41) is pushed forward, a connecting operation of two housings (10, 70) proceeds and the slider (40) is moved from the standby position to the connection position.