To restore transparency by efficiently polishing the whole surface of a panel for a short period of time without replacing a globe box panel even if the transparency of the globe box panel is lowered due to aging including degradation in radiation, dust scattering and the like.

A polishing main body to be driven by a motor, is provided with a first rotation holder 30 having a magnet 31 built in, and with three interval holding poles 14 arranged around the holder 30 so as to be equally divided in angle along its outer circumference. A panel outer surface is polished by letting a plate 32 attracted to the surface of the first holder 30 by means of magnetic force, and an abrasive paper stuck over the surface of the plate so as to be easily peeled off, or a buff, be rotated while the polishing main body is being moved along the panel surface with ball bearings 15 at the tip ends of the interval holding poles 14 pressed onto the outer panel of a globe box panel P. A second rotation holder 40 is attracted to the inner surface of the panel by means of magnetic force so as to be held at the position faced to the first rotation holder 30, and the second rotation holder 40 is also rotated together with the first rotation holder 30, so that the inner surface of the panel is also polished up.