PURPOSE: To increase the radiating efficiency of a radiator, by forming a radiating layer of far infrared rays on the surface of the storage tank of a radiator for air heating.

CONSTITUTION: A storage tank 2 is composed of heat transfer pipes 1 consisting of storage pipes of hot-water type or of heat pipes of which heating medium is a fluorinated hydrocarbon compound. A layer 3 to radiate heat of far infrared rays made of ceramics of zirconia, titania, mullite, or the like is formed on the surface of a storage tank 2. As for a heat accumulating material, one such as Na2SO410H2O of which heat accumulating rate per unit volume is large can be used. A heat insulating layer 4 made of expanded polyurethane or the like is formed on the back of a storage tank 2. With such an arrangement, a radiating layer 5 is heated by the accumulated calorific value, and the heat is radiated as radiation heat of long wavelength in the high temperature range. Accordingly highly efficient radiating effect can be obtained from a radiator.