TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Device: The hydrogen producing device comprises on/off combination of two or more valves which provide a preset flow and sets supply amount of each material. The hydrogen producing device comprises supply systems for air, oxygen or oxidizing agent and at least one type of material with flow setting units (2a,2b,3).At least one of the flow setting units and at least one of the material comprise parallel connected on/off valves.At least one of the on/off valves comprises a constant-flow valve and/or governor connected in series with the on/off valves. The flow setting unit is a discharge-controllable blower. The power generation system comprises a hydrogen storage unit provided after an outlet of the hydrogen producing device. The distributed power source further comprises exhaust heat recovery unit for recovering exhaust heat generated in the fuel cell using coolant. The recovered exhaust heat is used as hot water.Preferred Process: The supply amount of air, oxygen or oxidizing agent is set by controlling opening of a variable-flow valve, supply pressure of air oxygen or oxidizing agent and/or discharge of the discharge-controllable blower, such that the reaction portion has predetermined temperature. The supply amount of each material is set by selecting one from n1 set of predetermined values corresponding to required hydrogen production volumes. The supply amount of air, oxygen or oxidizing agent is set by selecting one from predetermined n2 set of values, where n1 is less than n2.Flow setting is performed, such that at least one of the flow setting unit opens the supply system during a time period (T2) in a preset time period (T1) and an average supply flow in the time period (T1) reaches a desired value. The time period (T1) is varied based on the status of hydrogen production operation such as alteration of required hydrogen production value.The hydrogen producing device produces hydrogen by a combined reforming method which involves employing combination of an exothermic reaction and an endothermic reaction.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: At least one type of material contains water (1b) and methane (1a), water and methanol or an aqueous solution of methanol.