To obtain a coolant useful as a portable coolant, capable of maintaining cooling performance for a long period of time, by supporting one or both of a refrigerant not containing water of crystallization and a refrigerant containing water of crystallization on a porous material, carrying out cooling by brining both the refrigerants into contact with each other.

This coolant carries out cooling by bringing (A) a refrigerant such as ammonium nitrate or ammonium (dihydrogen) phosphate not containing water of crystallization into contact with (B) a refrigerant such as sodium thiophosphate.5 hydrate or strontium hydroxide.8 hydrate. One or both of the component A and the component B are supported on (C1) a porous material such as silica gel or a cellulose (derivative) and the surface of the component B is coated with (C2) a polymer substance such as gum arabic or polyvinylpyrrolidone or the component A is supported on the component C1 and the surface of the component B is coated with the component C2.