PURPOSE: To correct the drooping of a shielding body drooping via the tare weight when it is folded and smoothly store it in a storage section.

CONSTITUTION: This shielding device for a ceiling is provided with a bellows-like shielding body 11 foldable in the opening region of a square frame body 10 provided at the light collection section or opening section 2 of the horizontal or inclined ceiling. Both ends in the opening/closing direction of the shielding body 11 are supported by support frames 12, 13 at least one of which is made movable, the movable support frame 12 is held movably in parallel, and a wire 14 is arranged to hold the shielding body 11. The storage section of the shielding body 11 folded between both support frames 12, 13 is formed, and a guide section 17 guiding the shielding body 11 to the storage section while correcting the drooping of the shielding body 11 when it is folded is provided at least at the lower edge section of one of the support frames 12, 13. This shielding body 11 can be smoothly stored in the storage section while its drooping is corrected.