PURPOSE: To enable a running route floor surface to be always cleaned, and contrive the running safety of an unmanned carrier by providing the external surface of a safety bumper with an insulating cleaner bearing, to fit a cleaner with a conductive brush, removably, and by connecting the cleaner and the unmanned carrier to each other with conductive material.

CONSTITUTION: On the external surface of the external cover 7 of the safety bumper 2 of a lower end section at the front and rear ends of an unmanned carrier, the cleaner bearing 10 of an elastic body having insulating property is firmly set, and on the cleaner bearing, a cleaner 12 having a brush 11 is removably fitted. Then, the cleaner is connected to the carrier 3 via a lead wire 14 having a diode 13 at an intermediate section. By said composition, static electricity generated in the unmanned carrier flows to the cleaner with the brush via conductive material, and flows to a floor. In its case, the brush is charged with the static electricity, and dropped substance on a running route floor surface is attracted, and the running floor surface is always beautifully cleaned, and the unmanned carrier can be run with safety and at high precision.