PURPOSE: To secure an easy trimming of the light absorbing film with no use of the NH4F solution, and thus to eliminate the defect on the fluorescent screen caused by the trimming solution.

CONSTITUTION: Photo resist 12 is coated on the inner surface of valve 1, and the latent image is formed by the ultraviolet rays given from radiation part 9a and 10a of light diffuser 9 and 10 in device 5. Panel 1 turns around the center axle to obtain the latent image of a fixed shape on the entire circumference of skirt 1b and seal surface 1c. Then shadow mask 13 is mounted to form the latent image on film 12 on the inner surface of face plate 1a via light control filter 15, correcting lens 16 and mask 13 respectively. Then the hot water is sprayed to remove the film except for the latent image part, and hardened film 17 is obtained. Then graphite suspension 18 is coated and dried. After this the exfoliation solution is injected to lift off film 17, thus forming light absorbing film 2 with which the trimming is over on the surface of panel 1.