A connector has a housing (20) with a recess (21). A moving plate (50) is located at an initial position in the recess (21) by a resilient restoring force of a spring (40) with a slider (30) held at a returning position in the recess (21). A mating connector moves the moving plate (50) to a connection position in this state and a resilient restoring force is accumulated in the spring (40). If the state of the slider (30) held at the returning position is canceled with the mating connector properly connected and the moving plate (50) at the connection position, the resilient force accumulated in the spring (40) is released as the slider (30) is moved to a releasing position. Thus, the spring (40) is free from permanent set in fatigue.