Provided is a method for causing a dehydrofluorination reaction of 1,1,1,3,3-pentafluoropropane in the gas phase and in the presence of a catalyst thereby producing 1,3,3,3-tetrafluoropropene. In this method, the reaction is carried out at a pressure inside the reaction system of from 0.001 to 90 kPa (absolute pressure) at a reaction temperature ranging from 250 to 600° C.