TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Process: A fluid (A) is introduced into the anode, a fluid (B) is introduced into the cathode, and the ion electroconductive material having oxygen ion electroconductivity picks-out electric power from the cathode and anode. A fluid (C) is introduced into the anode, a fluid (D) is introduced into the cathode, and the ion electroconductive material having oxygen ion electroconductivity switches on electric power from cathode and anode. Preferred Apparatus: The electrochemical reaction apparatus comprises MEA of cylindrical component, heater for heating MEA to working temperature of more than normal temperature, collector (A) which touches electrode (A) and is formed with conductor wire. The heater is provided in the inner surface side of MEA of cylindrical component. The collector (A) is contacted to inner surface of cylindrical component by thermal expansion of conductor wire at working temperature, without using conductive connection material. The collector (A) at normal temperature is capable of stretching elastically along longitudinal direction, and has reduced outer diameter. The collector (A) is formed with three-dimensional single stroke drawing-wire passed along the inner surface side of MEA of the cylindrical component. Joining and/or knitting process is carried out to form multiple conductor wire of collector (A). The collector (A) is a self-expansion type stent structure which supports MEA from the inner surface side at working temperature. A gas containing ammonia is eliminated by flowing ammonia to inside portion of MEA and contacting the outer side of MEA with air. The MEA of cylindrical component is straight-cylinder component, curved-cylindrical component, zig-zag meander cylinder or helical cylinder.    TECHNOLOGY FOCUS - METALLURGY - Preferred Components: The anode and/or cathode are sintered compacts containing metal particles-linked material having nickel as main component, and ion-conducting ceramics (22). The anode and/or cathode contain silver. The anode, ion electroconductive material and cathode form a flat plate or a cylinder. The anode is positioned in the inner surface side of cylinder, and the cathode is positioned in the outer surface side of cylinder. A collector of porous metal component is positioned in the opposite side to the ion electroconductive material of anode and/or cathode. The porous metal component is a metal-plating component.