There is provided a split cell type fuel cell stacks having a thin design and high-voltage and low-current output characteristics, in which a cell portion is divided into a plurality of sections electrically insulated from one another at both sides of a polymer electrolyte membrane. This fuel cell stack includes end plates, a unit cell provided between the end plates, a fuel distribution manifold provided in a central portion of the unit cell for supplying fuel thereto, a single tie bolt passing through a central portion of the fuel distribution manifold and the central portion of the unit cell so as to clamp the fuel cell components together into a unitary construction, and fixing nuts threaded respectively on both end portions of the tie bolt through washers, O-rings or the like to clamp the unit cell between the end plates. The cell portion includes a polymer electrolyte membrane, an oxygen electrode and a fuel electrode disposed oppositely on both sides of the polymer electrolyte membrane, a flow field plate disposed adjacent to the oxygen electrode, and a pair of separator plates contacting an outer side of the flow field plate and an outer side of the fuel electrode, respectively. Each of the fuel electrode and the separator plates, disposed on one side of the polymer electrolyte membrane, and each of the oxygen electrode, the oxygen flow field plate and the separator plate disposed on the other side thereof are divided into sections electrically insulated from one another.