A solid oxide fuel cell capable of extending the time period over which initial rated output power is maintained, while restraining increases in running cost. The present invention is a solid oxide fuel cell (1), having a fuel cell module (2) furnished with multiple fuel cell units, a fuel supply device (38), an oxidant gas supply device (45), and a controller (110) for controlling the amount of fuel supplied; the controller is furnished with a degradation determining circuit (110a) for determining degradation, and a fuel correction circuit (110b) for correcting the fuel supply amount based on the degradation determination; when it is determined that the fuel cell module has degraded, the fuel correction circuit executes a correction so that rated output power is maintained, and when the predetermined correction switching condition is satisfied, the fuel correction circuit executes a correction to reduce the fuel cell module rated output power.