The effect of current distribution on SPE water electrolysis was investigated using cur-rent feeders. The current distribution was estimated using the equation applied to brine electrolysis by Komagata. As the interval of the. bus bar, forming the current feeder, was altered from 30 to 5 mm, the current distribution was estimated to be unified. In the real experiment, the effect of the current distribution was tested by measuring the dissolved hydrogen concentration. At a slow liquid flow rate, the concentration of dissolved hydrogen did not impact on the order of the estimated current distribution, but conversely, at a high liquid flow rate, it increased as the estimated current distribution was rendered uniform. (c) 2005 Elsevier Ltd. All rights reserved.