A cell-voltage measuring structure for a fuel cell stack, in which a plurality of unit cells, having conductive separators which includes anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, respectively, are stacked in a stack direction, is provided with a voltage-measuring unit having a conductive voltage-measuring terminal, a contact section, with which the conductive voltage-measuring terminal is to be held in contact, formed on an outer periphery of a first pair of unit separators, a non-contact section, with which the conductive voltage-measuring terminal is not to be held in contact, formed on an outer periphery of a second pair of unit separators adjacent to the first pair of unit separators. A length of the conductive voltage-measuring terminal is greater than a thickness of the first pair of unit separators, in the stack direction.