PURPOSE: To keep humidity roughly constant in air in a shelf by fitting a panel on the recessed section of a shelf sheet from the upper side, and by composing the panel, of moisture regulating papers including powder bodies having moisture absorbing and removing function.
CONSTITUTION: A steel shelf sheet 10 is bent at the right angle upward from the front and rear edges of the bottom surface section 11, and the front and rear surface sections 12 are formed, and the sheet 10 is bent at the right angle inward from the upper edges of the front and rear surface sections 12, and turned back top surface sections 13 are formed. The internal edges of the turned-back top surface sections 13 are bent at the right angle downward, and reinforcing suspended sections 14 are formed. The cardboard external-plates 32 of the same material as the material of paper cores 31 fitted integrally on panels 30 are composed of moisture regulating papers including powder bodies of silica gel or the like having moisture- absorbing and removing function. Besides, on the whole surface of the external plates 32, a plurality of slots 33 are uniformly arranged. When on a recessed section on the bottom surface section 11 placed between the reinforcing suspended sections 14 of the shelf sheet 1 and the side surface sections 22 of reinforcing members 20, the panels 30 are fitted, then the panels 30 are fitted on the bottom surface section 11 of the shelf sheet 10. As a result, air in a space in a moisture regulating function book shelf 1 is not affected by the change of humidity in the ambient air, and is kept in roughly constant humidity for a long term. Then, books mounted on the shelf sheet 10 can be prevented from being damaged due to the change of the humidity for a long term.