The invention enables reduction of catalyst in producing tetrafluorobenzonitrile by decyanation of one cyano group of tetrafluorodicyanobenzene by using a synthetic zeolite, particularly Zeolite 3A, 4A or 5A, in the reaction. Therefore, the invention provides an industrially useful process capable of producing tetrafluorobenzonitrile, a useful agrochemical and drug intermediate, by hydrogenolysis of tetrafluorodicyanobenzene to decyanate one cyano group with the use of catalyst in small amounts.