In a fuel cell, a cell 105 including an anode 109, a solid electrolyte film 111 and a cathode 113 on an outer peripheral surface of a substrate tube 103 is formed in a circumferential direction of the substrate tube 103. A plurality of the cells 105 are arranged along a longitudinal direction of the substrate tube 103, and an interconnector 107 connecting the cells 105 electrically in series is formed between the adjacent cells 105. A thickness of an end portion of the cathode 113 in the longitudinal direction, the portion being in contact with the interconnector 107, is larger than a thickness of a center portion of the cathode 113 in the longitudinal direction. Thereby, high power generation performance can be achieved.