The fuel reservoir for a fuel cell is a fuel reservoir detachably connected with a fuel cell main body, and it is equipped with a fuel-storing vessel of a tube type for storing a liquid fuel and a fuel discharge part; the fuel discharge part is provided with a valve for sealing communication between the inside and the outside of the above fuel-storing vessel. The valve assumes a structure in which a slit is formed in an elastic material and a structure in which a valve member is pressed by a resilient body, and is opened by inserting a fuel-supplying member.