FUEL CELL AND FUEL CELL SYSTEM

PROBLEM TO BE SOLVED: To provide a fuel cell and a fuel cell system excellent in output characteristics.SOLUTION: The fuel cell comprises a power generating part having a membrane electrode assembly 3 containing an anode 21, a cathode 24, and an electrolyte membrane 27, and a fuel supply 7. At least the anode 21 side of the power generating part has selectivity so that the average open circuit voltage per cell is 0.4 V or lower in the last 30 minutes when the fuel supply 7 continuously supplies the cathode 24 side with a methanol with a 99 wt.% concentration or more at a speed of 0.2 μL/(min cm) for 3 hours with the power generating part disposed so that the cathode 24 faces the fuel supply 7. The membrane electrode assembly 3 can let a reaction product produced at the anode 21 side escape to the cathode 24 side, and can lead a reaction product produced at the cathode 24 side to the anode 21 side.