PURPOSE: To extend cold insulation time dramatically by providing two inner bags, mixing a hydrate agent and an endothermic agent contained in the inner bags to cause endothermic reaction, separating low temperature at least in two occasions, and embodying said endothermic reaction with time lag.

CONSTITUTION: A cold insulation pack 11 comprises a first hydrate 12A, a second hydrate 12B and an outer bag 15 which contains an endothermic agent 13 and a polymeric water absorption agent 14 as well. The inner bags 12A and 12B contain a water absorption agent 16. When a seal breaking thread 17A is pulled out, the water absorption agent 16 in the inner bag 12A and the endothermic agent 13 in the outer bag 15 are mixed with each other, thereby causing endothermic reaction. The water separated by the endothermic reaction is absorbed by the agent 14, turned into get state and stabilazed, thereby providing smooth and good feeling to the skin. Then, the inner bag 12B is also opened in a similar manner. The water absorption agent 16 is added so as to cause further endothermic reaction. It is, therefore, possible to obtain temperature at which cold can be felt and extend said cold feeling time.