A solid oxide fuel cell comprising: a fuel cell module furnished with multiple fuel cell units; a fuel supply device for supplying fuel to the fuel cell module; an oxidant gas supply device for supplying oxidant gas to the fuel cell module; and a controller for controlling the amount of fuel supplied from the fuel supply device, wherein the controller is furnished with a fuel correction circuit; characterized in that the controller is further furnished with a degradation determining circuit for determining degradation of the fuel cell module, wherein the fuel correction circuit is configured to correct the operating condition based on the degradation determination performed by this degradation determining circuit; wherein if it is determined prior to the satisfaction of predetermined correction switching condition by the degradation determining circuit that the fuel cell module has degraded after the start of initial operation of the fuel cell module, the fuel correction circuit executes a correction to decrease the fuel supply amount supplied to the fuel cell module so that rated output power, which is the maximum power output from the fuel cell module, is reduced, while on the other hand, after degradation of the fuel cell module advances and the predetermined correction switching condition is satisfied, the fuel correction circuit corrects the fuel supply amount supplied to the fuel cell module so that the fuel cell module rated output power at the time of when the predetermined correction switching condition is satisfied,is maintained; and wherein the predetermined correction switching condition is: a rise in fuel cell unit temperature to a predetermined correction switching temperature or above, a decrease in fuel supply amount to a predetermined correction switching fuel supply amount or below, a decrease in fuel cell module output power to a predetermined correction switching power or below, or a decrease in fuel cell module output voltage to a predetermined correction switching voltage or below. a fuel cell module furnished with multiple fuel cell units; a fuel supply device for supplying fuel to the fuel cell module; an oxidant gas supply device for supplying oxidant gas to the fuel cell module; and a controller for controlling the amount of fuel supplied from the fuel supply device, wherein the controller is furnished with a fuel correction circuit; characterized in that the controller is further furnished with a degradation determining circuit for determining degradation of the fuel cell module, wherein the fuel correction circuit is configured to correct the operating condition based on the degradation determination performed by this degradation determining circuit; wherein if it is determined prior to the satisfaction of predetermined correction switching condition by the degradation determining circuit that the fuel cell module has degraded after the start of initial operation of the fuel cell module, the fuel correction circuit executes a correction to decrease the fuel supply amount supplied to the fuel cell module so that rated output power, which is the maximum power output from the fuel cell module, is reduced, while on the other hand, after degradation of the fuel cell module advances and the predetermined correction switching condition is satisfied, the fuel correction circuit corrects the fuel supply amount supplied to the fuel cell module so that the fuel cell module rated output power at the time of when the predetermined correction switching condition is satisfied,is maintained; and wherein the predetermined correction switching condition is: a rise in fuel cell unit temperature to a predetermined correction switching temperature or above, a decrease in fuel supply amount to a predetermined correction switching fuel supply amount or below, a decrease in fuel cell module output power to a predetermined correction switching power or below, or a decrease in fuel cell module output voltage to a predetermined correction switching voltage or below.