To provide a light-shielding structure for a light-shielding photosensi tive material roll which can maintain light-shielding performance even when applied with a shock of vibration or falling.

The light-shielding structure for the light-shielding photosensitive material which has the photosensitive material roll configured by winding a hollow core with a photosensitive material sheet, and a couple of light-shielding flanges each comprising a cylinder part which is fitted onto a hollow part of the photosensitive material roll and a flange part which shades both the axial flanks of the photosensitive material roll has a press part, which presses a core internal wall of the photosensitive material roll, on the cylinder parts of the light-shielding flanges at least two places.