To prevent a generation of freezing of a refrigerant while preventing an increase of filling amount of an adsorbent, and also to prevent an inner corrosion of components.

A drier for a refrigeration cycle is applied to a vapor compression type refrigeration cycle where a refrigerant flows. As the adsorbent 31, a porous body (for example, B type silica gel, etc.) mainly containing silicon dioxide, and having adsorbent characteristics to increase adsorption characteristics of adsorbing ratio of water, following the increase of a relative humidity with respect to a relation between the relative humidity and the adsorbing ratio of water, is adopted. Hence, the increase of water permeability rate is prevented compared with zeolite, and the amount of water in the refrigerant is efficiently lowered, and the inner corrosion of is prevented. Then, through combination of the refrigerant having characteristics to hardly generate a subsumption component by a reaction to water, and the adsorbent 31 having a lower adsorbent performance while a low water concentration in the refrigerant, the generation of the freezing of the refrigerant is prevented while the increase of filling amount of the adsorbent 31 is also prevented.