A housing (10) is formed with a partial locking stopper (21) and a full locking stopper (24). A slide lever (25) (operating member) is formed with a single hook (33) having a partial locking contact surface (35) and a full locking contact surface (36). The partial locking contact surface (35) is at an acute angle to a sliding direction of the slide lever (25) and restricts a movement of the slide lever (25) at the partial locking position in a direction separating from the housing (10) by contacting the partial locking stopper (21). The full locking contact surface (36) is at an obtuse angle to the sliding direction of the slide lever (25) and restricts a movement of the slide lever (25) at the full locking position toward the partial locking position by contacting the full locking stopper (24) in a semi-locked state.