Abstract: A fuel cell having excellent properties is provided in which, when an enzyme is immobilized in at least one of a positive electrode and a negative electrode, a sufficient buffering capability can be provided even in a high power output operation and the inherent capability of the enzyme can be sufficiently exerted. In a biofuel cell including a structure in which a positive electrode 2 and a negative electrode 1 face each other with an electrolyte layer 3 therebetween, the electrolyte layer 3 containing a buffer material, and the biofuel cell including an enzyme immobilized in at least one of the positive electrode 2 and the negative electrode 1, the electrolyte layer 3 contains a compound including an imidazole ring as a buffer material and at least one acid selected from the group consisting of acetic acid, phosphoric acid, and sulfuric acid is further added to the electrolyte layer 3.

Abstract: In the case in which a fuel cell has a structure in which a cathode (2) and an anode (1) are opposed with the intermediary of an electrolyte layer (3) and the cathode (2) is formed of an electrode to which an oxygen reductase and so on is immobilized and this electrode has pores inside, at least part of the surface of this electrode is rendered water repellent. For example, the surface of the electrode is rendered water repellent by forming a water-repellent agent on the surface of this electrode. Thereby, in the case in which the cathode is formed of an electrode to which an enzyme is immobilized and this electrode has pores inside, a fuel cell that can stably achieve a high current value by optimization of the amount of water contained in the cathode and a manufacturing method thereof are provided.