Provided are high-performance gas desulfurizing agent and desulfurizing method each of which has a high desulfurizing ability even at low temperatures and keeps its desulfurizing performance for an extended period of time. The gas desulfurizing agent includes zinc oxide, aluminum oxide, and copper, the desulfurizing agent further including nickel in an amount of 1.0% by mass to 10% by mass and rhenium in an amount of 0.1% by mass to 1.0% by mass. The gas desulfurizing method includes bringing the desulfurizing agent into contact with gas in coexistence of hydrogen to decompose a sulfur compound in the gas and remove the sulfur compound from the gas.