PURPOSE: To easily perform the maintenance operation of an equipment arranged on the back face side of a door by guiding the light of an illuminating lamp arranged in an exhibition room through a communicating hole to the back face side of the door.

CONSTITUTION: An illuminating lamp 20 arranged in an exhibition room 17 of the back part of a partition plate 19 is supported by a back face member 15. Then, a communication hole 30 passing through the back face member 15 and communicating from inside the exhibition room 17 to the back face side of a door 2 is prepared. Then, when a cover 34 is opened by moving it right-and-left while holding a handle 36, the back face side of the door 2 is irradiated with the light of the illuminating lamp 20 passing through the opened communicating hole 30 and a shielding plate 32 towards the back part, so that entire of the back face of the door 2 can be illuminated. And also, when a cover 35 is opened by moving it back-and-forth while holding a handle 37, the back face side of the door 2 is irradiated with the light of the illuminating lamp 20 passing through an opened communicating hole 31 and a shielding plate 33 towards the lower part, so that the lower side of the exhibition room 17 of the back face side of the door 2 can be locally illuminated.