A method of producing 1,1,1,3,3-pentafluoropropane wherein 1,1,1,3,3-pentafluoropropane is obtained by reacting at least one selected from the group consisting of fluorinated and chlorinated propane and chlorinated propane expressed by a general formula of CX3CH2CHX2 (where X in this general formula indicates either a fluorine atom or a chlorine atom, but all of X's can never represent fluorine atoms at the same time) with a fluorinated antimony chloride. There is provided an economical and efficient method of producing 1,1,1,3,3-pentafluoropropane with high yield, which is an alternative compound to CFC's and HCFC's and is important in industry as a blowing agent, a refrigerant, a detergent, and a propellant that does not destroy the ozone in the ozone layer.