An assemble-type multi-stage microreactor with thin film catalyst has been developed. A new thin membrane carbon catalyst loaded with Cu/Zn is prepared through the carbonization of polyamic acid membrane loading Cu and Zn by ion exchange method. Using the microreactor with the catalyst developed, we perform steam reforming of methanol in order to selectively produce hydrogen for fuel cell usage. The methanol conversion and yield of H-2 reached 0.74 and 2.2 mol mol-methanol(-1), respectively, at the low temperature of 220 degrees C when using a 15-stage microreactor. As compared with the yields by a conventional tubular reactor, the methanol conversion is high and the CO yield is significantly suppressed in the microreactor. The advantage of the microreactor is presumably due to the concentration profile under a gaseous laminar flow in the micro space. Finally, the compact reactor system, which consists of a micro-reformer, micro-combustor and tubular-combustor, has been developed, and high yield of hydrogen and less than 5 ppm of CO has been successfully achieved.