A fuel cell which can self-heat in a short time, in which no reaction gas
is necessary for combustion, thereby improving the starting performance
at low temperatures. The fuel cell comprises a cell structure in which an
anode and a cathode are provided on either side of a solid polymer
electrolyte membrane. This cell structure has a power generation plane
and at least a part of the generation plane is defined as a local
generation area so as to locally generate power. The fuel cell may
include a pair of separators between which the cell structure is placed,
and a reaction gas passage may be formed between the cell structure and
each separator. One of a system for supplying a reaction gas to only a
part of the reaction gas passage, and a system for supplying a reaction
gas to the entire reaction gas passage is switchably selected.