An apparatus for measuring a cell pitch of a fuel cell stack, the fuel cell stack including a plurality of unit cells stacked in a stacking direction, wherein each unit cell has a membrane electrode assembly (MEA) interposed between a pair of metal separators, is provided. The apparatus includes a detector configured to generate a magnetic field in response to application of a current while being moved along the stacking direction of the unit cells, and sense an induced current generated in the separators by the generated magnetic field to detect positions of the separators.