PURPOSE: To provide a cooling device in a large-sized image display device which can prevent blow-by of a wind from the front of a display part through the display part, and can display beautifully an image without dispersion of colors.

CONSTITUTION: A display part 2 in which a plurality of display units 3 consisting of a plurality of light emitting elements are arranged, is provided on the front side in a building 1. A partition plate 4 is provided behind the display part 2, and a plurality of blowers for cooling the display part 2 are provided on the opening parts 4a of the partition plate 4. The intake 6 of cooling air is provided on the back lower part of the building 1, and a plurality of motor-driven dampers 9 are provided on the leeward side. The number of opening/closing set of the motor-driven dampers 9 are controlled according to the open air temperature. When the open air temperature is low, the number of opened set of the motor-driven dampers 9 is reduced, so as to prevent blow-by of a wind from the front face of the display part 2 through the cooling air intake 6.