To provide a cold storage agent that is furnished with a temperature monitoring function by color comparison and makes it possible to visually determine, by the color of the cold storage agent, the degree of cold storage in a forcibly cold-storing process in a refrigerator and the remaining cold storing ability while in use, of a common cold storage agent.

Microcapsulated reversibly temperature-indicating organic pigment (2a) is added to a common cold storage agent (1) made of a chemical material as a raw material to obtain the objective cold storage agent (A) with uniformly blended and dispersed components in which the degree of cold storage can be detected by color comparison by utilizing its color developing or color erasing function in the temperature indicating range of the pigment. Alternatively, a common cold storage agent (1) can be uniformly dispersed and blended with the microcapsulated pigment (2a) and a common pigment (3) having a different color. Further alternatively, a common cold storage agent (1) is blended and dispersed with the microcapsulated pigment (2a) and another microcapsulated reversibly temperature-indicating organic pigment (2b) that has a different temperature-indicating range and a different color.