An object is to provide a mixed refrigerant having four types of performance, i.e., a coefficient of performance and a refrigerating capacity that are equivalent to those of R410A, a sufficiently low GWP, and a lower flammability (Class 2L) according to the ASHRAE standard. Provided as a means for a solution is a composition comprising a refrigerant, the refrigerant comprising trans-1,2-difluoroethylene (HFO-1132(E)) and trifluoroethylene (HFO-1123) in a total amount of 99.5 mass % or more based on the entire refrigerant, and the refrigerant comprising 62.0 mass % to 72.0 mass % of HFO-1132(E) based on the entire refrigerant.