A fuel cell system (1,100) adapted to be installed on a moving object, comprising: an electric power generating element including a fuel cell supplied with fuel gas and oxidizing gas to generate electric power; a controller controlling the operation of the fuel cell system (1; 100) and being adapted to receive a control signal depending upon an operation content inputted by a user, which is transmitted from an external remote operator unit and commands a start-up completion time at which start-up of the fuel cell system (1,100) is to be completed through a warm-up of the electric power generating element, and to control the warm-up of the electric power generating element to be completed in alignment with the start-up completion time; a warm-up mechanism configured to warm up the electric power generating element operated by combustion; a warm-up mechanism configured to warm up the electric power generating element operated by electric power; and wherein the controller is configured to select and control one of the different warm-up mechanisms in response to the received control signal and dependent on conditions related to the start-up of the fuel cell, the conditions comprising: the time remaining from the current time to the start-up completion time; and the temperature of the electric power generating element, and the controller is thereby configured to initiate the warm-up of the electric power generating element with the one of the different warm-up mechanisms, as selected by the controller at a time prior to the start-up completion time commands by the external operator unit. an electric power generating element including a fuel cell supplied with fuel gas and oxidizing gas to generate electric power; a controller controlling the operation of the fuel cell system (1; 100) and being adapted to receive a control signal depending upon an operation content inputted by a user, which is transmitted from an external remote operator unit and commands a start-up completion time at which start-up of the fuel cell system (1,100) is to be completed through a warm-up of the electric power generating element, and to control the warm-up of the electric power generating element to be completed in alignment with the start-up completion time; a warm-up mechanism configured to warm up the electric power generating element operated by combustion; a warm-up mechanism configured to warm up the electric power generating element operated by electric power; and wherein the controller is configured to select and control one of the different warm-up mechanisms in response to the received control signal and dependent on conditions related to the start-up of the fuel cell, the conditions comprising: the time remaining from the current time to the start-up completion time; and the temperature of the electric power generating element, and the controller is thereby configured to initiate the warm-up of the electric power generating element with the one of the different warm-up mechanisms, as selected by the controller at a time prior to the start-up completion time commands by the external operator unit. the time remaining from the current time to the start-up completion time; and the temperature of the electric power generating element, and the controller is thereby configured to initiate the warm-up of the electric power generating element with the one of the different warm-up mechanisms, as selected by the controller at a time prior to the start-up completion time commands by the external operator unit.