NOVELTY - A pressure pipe (124) communicates with the water container (164) where water stored does not reverse flow toward the distributor (112) through it. A fuel supplying pipe (121) communicates with the mixer (130). The water supplying pipe (122) communicates with the mixer and with the water container where water can be smoothly supplied. A mixed fuel supplying pipe (123) communicates with the mixer and the reformer (140). A first check valve (128) has a water recovering pipe communicating with the water container.    USE - For a polymer electrolyte membrane fuel cell system used in an electricity generator.    ADVANTAGE - The airtight fuel container resists pressure and stores butane fuel. It does not deform in a temperature of 50 degrees Celsius and pressure of 1.5 times higher than the gas pressure. It does not rupture in the same temperature and pressure of 1.8 times higher than the gas pressure in the container. When the nozzle of the fuel container is opened, the butane fuel filling is discharged due to the internal pressure. Then, the amount of gas in the upper space decreases to lower the internal pressure. The pressure applied to the surface of the liquid is also lowered which gasifies the liquefied butane fuel. Without providing an additional fuel supplying unit, the butane fuel can be continuously supplied as the nozzle of the fuel container is opened. The reformer reduces carbon monoxide from the reformed gas through a water gas shift catalyst reaction and a preferential oxidation catalyst reaction.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for    (a) apparatus for supplying mixed fuel;    (b) fuel cell system    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the fuel cell including a mixed fuel supplying unit.    Distributor (112)    Fuel supplying pipe (121)    Water supplying pipe (122)    Mixed fuel supplying pipe (123)    Pressure pipe (124)    First check valve (128)    Mixer (130)    Reformer (140)    Water container (164)