Recent advances in micro-fuel cells have increased the demand for hydrogen. Therefore, a micro-reformer must be developed. Numerous portable electric devices are extremely small and reformers must therefore be shrunk and combined with micro-fuel cells. The mass production of micro-reformers raises various problems that are yet to be solved. such as the measurement of their internal temperature and flow rate. Such issues influence the efficiency of the micro-reformers. To our knowledge, no investigation has yet properly elucidated the internal operation of micro-reformers. Accordingly, in this work, a flexible micro-temperature sensor, a micro-heater, a micro-flow sensor and the flow field of a stainless steel-based micro-reformer were fabricated by micro-electro-mechanical-systems (MEMS) fabrication technique. The fabrication technique has the advantages of (1) small size, (2) flexible but precise measurement positions, and (3) mass production process. (C) 2009 Elsevier B.V. All rights reserved.