A
fuel gas generation device comprises a compartment containing a
solid component and a chamber containing a liquid capable of causing a
fuel gas generating
chemical reaction when in contact with said
solid component. A liquid permeable member is disposed between the compartment and the chamber and in contact with said
solid component and a liquid supply
system is disposed and arranged for delivering liquid from the chamber to the permeable member at a fixed rate. The device also includes a first
chemical reaction space adjacent the permeable member where the
fuel gas generating
chemical reaction occurs and a second chemical reaction space linked to the first space. The volume of the first space is smaller than the volume of the second space. The device is useful for multiple purposes and generates and supplies a constant amount of fuel gas for mobile and portable
fuel cells and the like continuously, stably, conveniently and inexpensively without using pressure adjusting valves and the like. The device includes a
system capable of being applied to a wide range of uses for amounts of fuel gas. The operation of the device to maintain a constant
reaction rate is based on the concentration of an oxidation catalyst material dissolved in the liquid, the performance of a solid oxidation catalyst material, the liquid supply rate, and / or the size of the surface area of a permeable member in contact with the liquid. The device is useful for maintaining a constant chemical
reaction rate regardless or whether the oxidation catalyst is in liquid or solid form.