A dehydrogenation system for formic acid was first constructed by using a two-compartment reactor separated by a palladized Pd sheet electrode. This was confirmed by an increase in oxidation current which arises after an induction period due to permeation of atomic hydrogen. In addition, the maximum oxidation current increased with palladization time or the amount of Pd black deposited. It is suggested by estimation of the roughness factor, that this result is to be ascribed to the extension of the reaction area. The maximum oxidation current increased with temperature: due to the usual Arrhenius activation energy effect for the dehydrogenation.