Provided is a solid oxide fuel cell system with which, while executing a shut-down interrupt, it is also possible to avoid restoring an air electrode. The present invention is a solid oxide fuel cell system (1), comprising: a fuel cell module (2); a fuel supply device (38); a water supply device (28); an air supply device (45); a reformer (20); and a controller (110) which controls the fuel supply device, the water supply device, the air supply device, and the extraction of electricity from the fuel cell module. The controller further comprises a shut-down interrupt circuit (110a) which, in a state of a fuel cell cell stack being at an oxidation suppression temperature or above, executes a shut-down interrupt. After the shut-down interrupt, in a period in which fuel electrode-side pressure is sufficiently higher than air electrode-side pressure, and a backflow of air to the fuel electrode side does not occur, the shut-down interrupt circuit executes a temperature lowering control which exhausts high-temperature air which remains on the air electrode side.