SPE type pure water electrolysis shows good performance for hydrogen generation. However, considering future hydrogen society, SPE electrolysis would face real difficulty to meet a large demand. Chlorine Engineers Corp., Ltd. (CEC) is one of the major electrolyzer manufacturers in the chlor-alkali industry and has great experience in cell design and cell technology. Zero gap system was applied for cell evaluation based on CEC technology. A special electric collector for cathode was used to create zero gap without damaging the separator. Cell voltage was 1.76V at 40A/dm2, 80 deg C without any problems. Raney Ni alloy coating had advantage for oxygen over-voltage. (100mV - 200mV saving against Ni metal) Thermal decomposition coating of cathode showed low hydrogen over-voltage. (around 100mV) Ion exchange membrane N117 and F8020 showed high cell voltage (over 2.2V) but low O2 impurity in H2 gas (over 99.95%). Porous polyolefin film showed 1.76V cell voltage but no durability.