FUEL CELL SYSTEM

A fuel cell system includes: a hydrogen generating unit that generates hydrogen-containing gas using hydrogen-containing fuel; a cell stack that performs power generation using the hydrogen-containing gas; a current acquiring unit that acquires an electric current of the power generation in the cell stack; a power generation state determination value acquiring unit that acquires a power generation state determination value based on measurement results of a power generation parameter of the power generation in the cell stack; an estimate value acquiring unit that acquires an estimated value of the power generation parameter that is predetermined for the electric current; a comparing unit that compares the power generation state determination value and the estimated value; and a supply amount adjusting unit that adjusts a supply amount of the hydrogen-containing fuel based on an increase or a decrease of the power generation state determination value in relation to the estimated value.