A cartridge 2 receiving a photosensitive recording disc 4 therein
including: a cartridge body 11 having inner openings 18 and 19 exposing
part of the recording disc 4 to the outside; a light-shield plate 12
attached to the outside of the cartridge body 11 and having outer
openings 14 and 15 which face the inner openings 18 and 19; and a shutter
13 opening/closing the inner openings 18 and 19 and the outer openings 14
and 15 between the cartridge body 11 and the light-shield plate 12;
wherein recesses 25e and 26e for inserting end edges 12d of the outer
circumference of the light-shield plate 12 are provided in light-shield
plate attachment surfaces 25a and 26a of the cartridge body 11 so that
when the end edges 12d are inserted into the recesses 25e and 26e and
attached to the cartridge body 11, a labyrinth-shaped light-shielding
structure is formed.