METHOD FOR PRODUCING HYDROFLUOROOLEFIN

There is provided a method of producing HFO with which diluent gas is easily separated even at a low boiling point and which has excellent productivity. A method of producing HFO includes: a reaction step of converting, in the presence of fluorine-containing compound in a gaseous state having a boiling point higher than a boiling point of HFO represented by the following formula (2), HFC represented by the following formula (1) into the HFO represented by the following formula (2), to obtain a first gas composition containing the HFO and the fluorine-containing solvent, CR 1 R 2 X 1 CR 3 R 4 X 2 (1), CR 1 R 2 = CR 3 R 4 (2), where in the formula (1) and the formula (2), R 1 to R 3 are H or F, R 4 is H, F, CH 3 , CH 2 F, CHF 2 or CF 3 , the total number of fluorine atoms of R 1 to R 4 is one or more, and the total number of hydrogen atoms of R 1 to R 4 is one or more, one of X 1 and X 2 is H, and the other of X 1 and X 2 is F; and a separation step of separating the fluorine-containing solvent from the first gas composition to obtain a second gas composition containing the HFO.