To raise the freezing effect by elevating the charge efficiency of an adsorbent.

This is an adsorber 1 making use of heat generating and absorbing reaction accompanying the reversible reaction between a granular adsorbent 6 and a refrigerant, and this is equipped with a heat exchange fluid passage where heat exchange fluid circulates, a plurality of plate fins 4 being arranged in parallel in condition of thermal contact with the heat exchange fluid passage, and corrugated fins 5 arranged between the adjacent plate fins 4. The space made by the plate fins 4 and the corrugated fins 5 is charged with an absorbent 6.