To resolve a problem in a homothermal refrigerant material mainly composed of sodium sulfate or the like wherein a refrigerant material not needing precedent cooling in a refrigeration environment can be obtained, but since it is basically in a liquid form, in actual use, it needs to be sealed in a bag like vessel comprising soft resin or the like, or filled and sealed in a watertight structure, and there is a significant constraint to usage application.

The cooling sheet material 1 is composed such that high cooling efficiency can be obtained by a small refrigerant material amount by using a felt like sheet comprising carbon pitch based carbon fiber as a structural base material 2, impregnating and holding the refrigerant material mainly composed of sodium sulfate, and applying a cover film 3 in a form including them. By this, in the cooling sheet, form setting, processing such as bending, and installation to a narrow space are facilitated, and since a watertight structure or the like is not necessary in arrangement, a wide application range can be provided.