A fuel cell system includes: a first fuel cell; a second fuel cell having a greater maximum power output than a maximum power output of the first fuel cell; and a controller configured to cause the first fuel cell to generate greater electric power greater than the second fuel cell when the requested power is smaller than a first threshold, cause the second fuel cell to generate greater electric power than the first fuel cell when the requested power is a second threshold, which is the first threshold or greater, or greater and is smaller than a third threshold that is greater than the second threshold and is greater than 50% of a sum of the maximum power outputs of the first and second fuel cells, and cause both the first and second fuel cells to generate electric power when the requested power is the third threshold or greater.