PURPOSE: To make it possible to increase cold insulation time dramatically to give a good feeling touch by providing two inner bags, generating the endothermic reaction through the mixture between a hydrate agent and an endothermic agent contained in the inner bags with the second inner bag opened a specified time after the first inner bag is opened.

CONSTITUTION: A cold heat material pack 11 comprises a first inner bag 12A, a second inner bag 12B, an outer bag 15 which contains an endothermic agent 13 and a polymeric water absorption 14 as well, and their coat 16. The inner bags 12A and 12B contain a hydrate agent 17. When a seal breaking thread 20 is pulled out, the hydrate agent 17 in the inner bag 12A is mixed with the endothermic agent 13 in the outer bag 15, thereby causing endothermic reaction. The water separated by the endothermic reaction is absorbed into the polymeric water absorption agent 14 and stabilized in gel state, and provides a good feeling touch with the coat 16 which is smooth to the skin. Then, the inner bag 12B is seal-opened in a similar manner and the hydrate agent 17 is added to cause further endothermic reaction. This construction makes it possible to extent and maintain the temperature at which cold feeling of the coat 16 can be enjoyed.