The present invention provides a fuel cell system including a fuel cell configured to cause reactant gas to be electrochemically reacted to generate electrical power when the reactant gas is supplied to the fuel cell, power consuming equipment such as a reactant gas supply apparatus and a heating device operable to consume electrical power generated by the fuel cell, and a controller for controlling operation of the fuel cell system. During a warm-up operation, the controller causes the reactant gas supply apparatus to start a flow of the reactant gas and to increase the flow of the reactant gas over time, such that the reactant gas supply device starts to consume power and consumes increased power over time. After starting the flow of the reactant gas, the controller causes the heating device to start heating the coolant such that the heating device consumes power.