A fuel cell stack is provided with a plurality of stacked separators. This fuel cell stack includes: terminals that extend from the separators; packing in which are formed a plurality of through holes through which the terminals are inserted; a packing casing that has a packing housing concave portion that envelops side surfaces of the packing and supports a bottom surface of the packing, and has through holes through which the terminals are inserted; and a connector housing that has a pressing surface that presses a top surface of the packing. Mountain-shaped protruding portions whose apex portions are formed by circumferential edges of apertures of the respective through holes are provided on the top surface of the packing, and the pressing surfaces of the connector housing are formed in a configuration that conforms to the side surfaces of the protruding portions. Internal surfaces of the through holes in the packing are in contact without a gap in between with external surfaces of the terminals. The sealing performance in extraction portions of terminals that are used for cell voltage detection is improved.