SOLID ELECTROLYTE FUEL CELL

The invention is a solid oxide fuel cell system (1) including: a fuel cell module (2), a fuel flow regulator unit (38), a first power demand detection device (110a), a control section (110) for controlling a fuel supply amount and setting the current value extractable from the fuel cell module, an inverter (54) for extracting current in a range not exceeding the extractable current value, and a power state detecting sensor (126) for detecting actual extracted current value; whereby if actual extracted current value declines, then under circumstances where power demand begins to rise in a state of extra margin in the fuel supply amount after the controller suddenly decreases the extractable current value and suddenly reduces the electrical collector, the controller increases the extractable current value at a high current rise rate of change.