PROBLEM TO BE SOLVED: To provide a local current measuring device measuring a local current of a fuel cell with a simple structure and a high accuracy, and a fuel cell diagnosis device diagnosing an operation state of the fuel cell with a simple structure and a high accuracy. SOLUTION: As seen from a laminating direction of a cell 21, a hydrogen side magnetic material core 51 is arranged so that a part thereof is exposed to an outside of the fuel cell 20 and that the remaining part thereof surrounds a region (local area) including a proximity of a fuel gas side outlet inside the cell 21, and an air side magnetic material core 52 is arranged so that the remaining part surrounds a region (local area) including a proximity of an oxidizer gas outlet inside the cell 21. Furthermore, at the part of the hydrogen side magnetic material core 51 and the air side magnetic material core 52 exposed to the outside of the fuel cell 20, the local currents flowing through the regions surrounded by the magnetic material cores 51, 52 are detected by magnetic sensors 54a, 54b detecting magnetic field intensity formed in the magnetic material cores 51, 52, respectively. COPYRIGHT: (C)2011,JPO&INPIT