[Problems] perform dehydrogenation of hydrocarbons, in the method for producing an unsaturated hydrocarbon with ethylene supplied as receptors of the resulting hydrogen, minimizing the loss of ethylene, and yield for a long time to provide a method for producing a rate well unsaturated hydrocarbons.
[SOLUTION] A method for producing a dehydrogenation reaction performed unsaturated hydrocarbons of a hydrocarbon in the reactor, the reactor, the first reaction zone, a second reaction zone disposed on the downstream side , and a connecting region for connecting the first reaction zone and the second reaction zone, the method comprising supplying a feedstock containing gas containing a hydrocarbon in the first reaction zone, the dehydrogenation of the hydrocarbon obtaining a primary product gas undergoes a reaction, and in the coupling region, the ethylene was mixed with the primary product gas, a mixed gas obtained was fed to the second reaction zone, the dehydrogenation reaction and the hydrocarbon method for producing an unsaturated hydrocarbon which comprises performing the reaction to produce ethane by adding the hydrogen to the ethylene.