A fuel cell system having a fuel pressurizing system. The fuel cell system includes: a cartridge comprising a fuel storage pack; a main body; and a pressurizing unit disposed in the main body to pressurize the fuel storage pack when the cartridge is mated to the main body. The cartridge further includes a pressurizing plate to transmit pressure received from the pressurizing unit to the fuel storage pack when the cartridge is mated to the main body and to preventing the fuel storage pack from being pressurized when the cartridge is separated from the main body. The main body can include a case on which the fuel storage pack and the pressurizing plate are received.