Small cylindrical reformer

The invention relates to a small cylindrical reformer, which is suitable for use in the production of hydrogen from fossil fuels for small fuel cell power plants. In the small cylindrical reformer according to this invention, a reforming reactor (32, 33, 36), a water gas shift reactor (37, 38, 39) (high temperature or low temperature), a combustor (10, 13, 14), a heat exchanger (53), a steam generator, etc., may be integrated in a single container to form an optimal heat exchanging network, minimize heat loss and optimize heat exchange efficiency. Thereby, the reformer is designed to be easily processed and manufactured and to have a compact size, thus realizing high efficiency, light weight and ease of mass production.