A device for measuring stack voltage includes a stack part and a connector. The stack part includes terminals of a bipolar plate extending outward from a side of the bipolar plate, a gasket combined with the bipolar plate, a sub-gasket combined with the gasket and having extensions laterally protruding corresponding to the terminals. The connector has insertion grooves in which the terminals are disposed at a front of the connector. A plurality of wires pass forward from behind through the connector. The connector has sensing units that are disposed in the insertion grooves, connected to front ends of the wires, and are in contact with the terminals of the bipolar plate when the connector is combined with the stack part.