Provided is a sheet chemical cell of a simple and easy-fabricated structure having a small number of parts that can improve the energy density strikingly, a manufacturing method thereof, a fuel cell, and a manufacturing method thereof. Also provided is a sheet chemical cell including a plurality of unit cells each of which includes an electrolyte membrane, a plurality of anode plates on one surface of the electrolyte membrane, and a plurality of cathode plates on the other surface of the electrolyte membrane, with the anode and cathode plates opposed to each other in pairs with the membrane therebetween, and slots through the electrolyte membrane so that wiring plates of respective anode and cathode plates are electrically connected through the membrane via the slots to provide cells connected in series.