A membrane reformer (MRF) in which the production and separation of hydrogen proceed simultaneously in a single reactor allows the production to proceed without the constraint of chemical equilibrium. An MRF can thus be made more compact and provide higher efficiency than a conventional reformer. In this study, a Pd-based membrane of less than 10 mu m in thickness was fabricated on a porous catalytic substrate, and a hydrogen production module was developed with the thin Pd-based membrane-on-catalyst (MOC) module. The steam reforming performance of the MOC module was evaluated under different conditions of city gas feed rate and temperature. At process side pressure/permeation side pressure of 0.90 MPa/0.04 MPa, the hydrogen production rate of the MOC module was 11.4 N cm(3)/(min.cm2) at a city gas feed rate of 3.0 N cm(3)/(min.cm2) and 547 degrees C, which is almost equal to the performance of the conventional membrane reformer system for hydrogen production.