Provided are a high-performance desulfurizing agent for gases and a gas desulfurization method that provide a high desulfurization performance even at low temperatures and can maintain its desulfurization performance for a long period of time. The desulfurizing agent is characterized in that it includes a zinc oxide, an aluminum oxide and copper, the agent further including nickel by from 1.0 mass% to 10 mass% and ruthenium by from 0.1 mass % to 1.0 mass %. The gas desulfurization method is characterized in that the desulfurizing agent is brought into contact with the gas in the coexistent of hydrogen, thus decomposing/removing sulfur compound contained in the gas.