A fuel production system and has an object to provide a fuel production system that is capable of producing HC with high efficiency by using variable energy. A first device is a CO/H2 generating device that simultaneously generates CO and H2 by performing electrolysis on CO2 and water. A second device is a H2 generating device that generates H2 by performing electrolysis on water. When electric power derived from natural energy is used, the first device is seriously affected by its variation. Therefore, a steady-state portion of generated electric power (straight line in a figure) is supplied to the first device while the remaining variable portion (the portion above the straight line) is supplied to the second device.