A moving plate (13) is inserted into a receptacle (11) of a connector body (12) and movable between a partial locking position and a connection position and includes partial locking portions (91) and resilient locking pieces (46). The partial locking portions (91) restrict movement of the moving plate (13) to the connection position. The resilient locking pieces (46) lock to receiving portions (75) of a mating connector (60) and allow movement from the connection position to the partial locking position by being kept locked to the receiving portions (75) while separating the mating connector from the receptacle (11). The connector body (12) has restricting surfaces (28) to restrict deflection of the resilient locking pieces (46) until a riding amount of the partial locking portions (91) on second interfering portions (36) is a maximum when the moving plate (13) returns from the connection position to the partial locking position.