A cold storage material composition is provided allowing for temperature maintenance of a temperature control target article in various control temperature ranges in a range of −75° C. to −55° C. and being capable of solidifying within a given period of time and (ii) a technique of using the cold storage material composition. Also provided is a cold storage material composition including calcium ions, chloride ions, bromide ions, and ammonium ions in respectively specific amounts, relative to 100 mol of water, and having a melting temperature in a range of −75° C. to −55° C.