To provide a nonsuction clean actuator of a dust preventive structure which needs not to reduce the pressure by an exhaust pump.

In a housing 1 having a slit on the outer surface, a member for conveyance 10 driven to reciprocate along the slit by a feeding device 16 which is supported in the axial direction through a linear guide device is provided, and while a part of the member for conveyance 10 is projected to the outer side through the slit, an auxiliary space 3 communicating to the outer side is provided along a main space 2 in the housing 1 where the member for conveyance 10 moves, un an actuator which is engaged with the movable loop, of a seat belt 25 extended in the housing 1 through plural pulleys 26, and blocking the opening of the slit, and the auxiliary space 3 and the main space 2 are communicated through exhaust valves which are set at both ends of the main space 2, and let flow the air only in one direction to the auxiliary space 3.