PURPOSE: To prevent a crack from spreading up to a shade surface and an external appearance design surface when the crack is generated from a square hole by arranging integrally molded walls inside of a shade of a part covered with a decoration so as to separate a decoration engaging structure part and a shade inside surface from each other.

CONSTITUTION: A luminaire shade device has shades 1 and 1' used by putting the same two V-shaped parts together and a decoration 2 to be elastically and repulsively engaged with a corner part of the shades 1 and 1' by claws 4. The shades 1 and 1' have engaging structure parts 5 and 5' composed of a square hole A in the corner part, and have the engaging structure parts 5 and 5' composed of the square hole A inside of a part covered with the decoration 2 and have the engaging structure parts 5 and 5' composed of the square hole A and walls 3 and 3' to separate a shade inside surface and an external appearance design part from each other inside of the part covered with the decoration 2. The walls 3 and 3' are integrally molded. Since stress is concentrated on the corner part of the square hole A, there arises the possibility of generating a crack C at elastically and repulsively engaging time of the decoration 2 and packed transportation time, but the progress is prevented at the root of the integrally molded walls 3 and 3'.