PURPOSE: To make it possible to observe the limit of dehumidifying ability by packing the whole of laminated sheets with a packing material formed with a microporous film permeable to steam but impermeable to water.

CONSTITUTION: The whole of a laminate consisting of a sheetlike hygroscopic body 1, a colored sheet 2 and a sheet 3 for confirmation is packed with a packing material 4 formed with a microporous film 4a such as a PP, polyamide or PVC film. Moisture in the air enters through the film 4a and is rapidly absorbed in the deliquescent substance of the hygroscopic body 1. Formed deliquescence is accumulated in the water retaining material 1b of the hygroscopic body 1. The sheet 3 for confirmation is swollen with the deliquescence oozing out of the material 1b and becomes see-through. Safety and hygiene are improved.