Fuel cell, electronic device and buffer solution for fuel cell

A fuel cell having an excellent performance, wherein sufficient buffering power can be obtained during high output operation when an enzyme is immobilized on a positive electrode and/or a negative electrode, and the enzyme can exert intrinsic abilities thereof sufficiently.  Specifically disclosed is a biofuel cell having a structure wherein a positive electrode (2) and a negative electrode (1) are arranged opposite to each other with an electrolyte layer (3) containing a buffering substance interposed therebetween, and an enzyme is immobilized on the positive electrode (2) and/or the negative electrode (1).  The electrolyte layer (3) contains, as a buffering substance, a compound having an imidazole ring, and at least one acid selected from the group consisting of acetic acid, phosphoric acid and sulfuric acid is added thereto.  Imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole or the like is used as the compound having an imidazole ring.