NOVELTY - A fuel cell-type reactor has an anode (4), a cathode (5), an anode chamber (1), a cathode chamber (3) and an intermediate chamber. The intermediate chamber is divided into anode side intermediate chamber (2B) and cathode side intermediate chamber (2A) by a diaphragm (12). The chambers (2B,2A) are respectively provided between anode and diaphragm, and cathode and diaphragm. An electrolytic solution is introduced between chambers (2A,2B). The anode and cathode are electrodes formed by supporting an electrode catalyst to carbon paper.    USE - Fuel cell-type reactor is used for producing hydrogen peroxide from hydrogen and oxygen.    ADVANTAGE - The fuel cell-type reactor has high efficiency and stability.    DETAILED DESCRIPTION - A fuel cell-type reactor has an anode (4), a cathode (5), an anode chamber (1), a cathode chamber (3) and an intermediate chamber. The intermediate chamber is divided into anode side intermediate chamber (2B) and cathode side intermediate chamber (2A) by a diaphragm (12). The chambers (2B,2A) are respectively provided between anode and diaphragm, and cathode and diaphragm. An electrolytic solution is introduced between chambers (2A,2B). The anode and cathode are mutually connected by electronic conductor. The anode and cathode are electrodes formed by supporting an electrode catalyst to carbon paper. The electrode catalyst of anode is platinum or an alloy containing platinum. The electrode catalyst of cathode is electroconductive carbon chosen from graphite, activated carbon, carbon black, acetylene black, carbon fiber, carbon nanotube, fullerene and/or Ketchen black. The support of catalyst to carbon paper is carried out using binder chosen from fluororesin and silicone. INDEPENDENT CLAIMS are included for the following:    (1) anode; and    (2) cathode.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view explaining manufacture of hydrogen peroxide.    Anode chamber (1)    Cathode side intermediate chamber (2A)    Anode side intermediate chamber (2B)    Cathode chamber (3)    Anode (4)    Cathode (5)    Ion exchange membrane (12)