NOVELTY - A hydrogen generator (10) consists of a reaction container (12), a liquid feeding flow path (15), a volume detector (28), and a supply controller (22). The reaction container has a storage portion (24) for reaction product of solid reaction material (11) and aqueous solution (13). The volume detector detects the volume of stored material (27). The supply controller controls the supply of aqueous solution by initial-stage flow volume, when detected value is below set volume. When detected value exceeds set volume, supply of aqueous solution is regulated.    USE - Hydrogen generator is used in fuel-cell systems (claimed) of power devices.    ADVANTAGE - The hydrogen generator enables favorable supply of aqueous solution for reaction, preventing bubbles of stored material from flowing oxide. A fuel-cell system using the hydrogen generator favorably supplies electric power over a long period of time.    DETAILED DESCRIPTION - A hydrogen generator consists of a reaction container, a liquid feeding flow path, a volume detector, and a supply controller. The reaction container has a storage portion in which the product produced during reaction of solid reaction material and aqueous solution is stored, while the solid reaction material which reacts with the aqueous solution and produces hydrogen is held. The liquid feeding flow path connects the reaction container and supplies the aqueous solution with respect to the solid reaction material. The volume detector detects the volume of stored material in the storage portion. The supply controller controls the supply of aqueous solution by initial-stage flow volume, when the detected volume value is below a specific set volume. When the detected value exceeds the set volume, the supply of aqueous solution is regulated.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the hydrogen generator. (Drawing includes non-English language text)    Hydrogen generator (10)    Solid reaction material (11)    Reaction container (12)    Aqueous solution (13)    Liquid feeding flow path (15)    Supply controller (22)    Storage portion (24)    Stored material (27)    Volume detector (28)