Abstract: A pusher cylinder for a tunnel kiln is used for moving kiln cars loaded with products such as molded ceramic green products to be sintered in the tunnel kiln. A piston rod of the pusher cylinder is made to have a length more than twice a stroke of the pusher cylinder. With such an arrangement, even if foreign substances such as tar are attached to the piston rod extended into the tunnel kiln, the substances do not enter the pusher cylinder in the fully retracted position of the piston rod. As a result, there is no longer any risk of the pusher cylinder itself and a packing for a piston of the cylinder being damaged by such foreign substances. Therefore, the life span of the pusher cylinder and packing until they need to be replaced is remarkably prolonged.