To provide a dehumidification material composition having a larger heat accumulation density and to provide a regenerating method for the dehumidification material composition capable of efficiently regenerating the dehumidification material composition having reduced dehumidification ability and more efficiently exchanging heat in an open type air conditioning system.

The dehumidification material composition is a dehumidification material composition for absorbing moisture content in air to carry out dehumidification and contains lithium chloride as a indispensable component. The dehumidification material composition further contains a salt (addition salt) for accomplishing total solubility of higher concentration of single saturation solubility of lithium chloride and itself by addition.