PURPOSE: To prevent surface damage and breakdown of the shielding layers of a mask and transparent glass substrate by the electric charge generated during production of the mask by providing an UV ray projection device which projects UV rays to the shielding layers of the mask.

CONSTITUTION: The UV ray projection device 4 is provided in the position opposite to the surface of the mask 1 held on a mask turn table 2. The UV ray projection device 4 is mainly constituted of a UV projection lamp and a reflector which condenses the UV rays from the UV ray projection device and is so constituted that the device can project the UV rays directly to the shielding layers 1B1W1B3 of the mask 1 surface at least during cleaning of the mask 1. The electric charges charged on the respective shielding layers 1B1W1B3 of the mask 1 during cleaning of the mask 1 are, therefore, excited by projecting the UV rays thereto. Leakage between the shielding layers 1B1 and 1B2 which proximate to each other and are different in size (different in the quantity of electric charge) (part C) is thereby prevented, and the surface damage and breakdown of the shielding layers 1B1 and 1B2 of the mask 1 or the transparent glass substrate 1A are prevented.