The methanation performance of a Ni/CeO2 structured catalyst having a spiral shape was investigated using a feed material gas containing 1-11 vol% oxygen. The spiral catalyst exhibited high methane yield for a high oxygen concentration (9-11 vol%) and fast feed flow rate even under an auto-methanation condition, which does not require external heating. Such high methane yield was continuously maintained for 60 hours or longer. Under the auto-methanation over the structured catalyst, the reaction field generated high thermal energy, which did not exceed the Tammann temperature of the nickel component, due to selective hydrogen combustion.