Abstract: A self-driving closure device for moving a closure member such as a window glass of a vehicle between an open position and a close position. The device has a motor movable together with the closure member. The motor has a pinion that meshes with a rack secured to the vehicle door or a rotary drum on which an intermediate portion of a wire secured to the door is wound, so that a thrusting force for driving the window glass between the open and close positions is generated as a reactional force as the pinion or the drum is rotated. A mechanism is provided between the motor and the window glass so as to absorb any offset between the direction of movement of the glass and the direction of movement of the motor, so as to ensure smooth movement of the window glass.