To obtain a refrigeration source device which can be easily produced by a user, can be conveniently handled, is freed from a hazard, can generate low temperature capable of cooling or refrigeration over a long period of time by holding a direct contact type refrigerant prepared by direct contact of a frozen solid with a freezing mixture in a heat-insulation space.

The freezing mixture is exemplified by a hydrochloride, a nitrate, a thiocyanate, an alkaline earth sulfate or hydrochloride n-hydrate or a mixture thereof. For example, it is a combination of NaCl with NH4NO3 or a mixture of KNO3 with NH4Cl. The frozen solid is the most suitably ice. The direct contact of the frozen solid with the freezing mixture can be practiced, for example, by previously making a frozen solid, placing it in a bag, and adding a freezing mixture to the bag so as to realize direct contact therebetween. It is necessary that the refrigerant is placed in a heat-insulation space such as a heat-insulation container made of e.g. foamed polystyrene to keep it in a closed state. The freezing mixture may be a concentrated solution instead of a solid.