PURPOSE: In reacting hydrogen in a coke oven gas with benzene, to obtain the titled compound efficiently without hindering hydrogenation reaction of benzene, by pretreating the gas so that concentrations of sulfur compounds and CO in the gas are reduced to ≤specific amounts and carrying out the reaction.

CONSTITUTION: In reacting hydrogen in a coke oven gas with benzene, Fe2O3 catalyst and ZnO-CuO are combined, used, the amount of sulfur compounds in the gas is reduced to ≤1ppm, then concentration of CO in the gas is reduced to ≤1% by shift reaction, hydrogen is reacted with benzene to give cyclohexene. When a nickel catalyst is used as the catalyst, the content of nickel is preferably 20W40%.