NOVELTY - A hydrogen generator (20) comprises a reactor (22) containing an aqueous solution of chemical hydride; catalyst to generate hydrogen by a chemical reaction between chemical hydride and water; transferring device for transferring catalyst into the solution and transferring the catalyst out of the solution; and temperature controller (24) for maintaining temperature of the solution at predetermined temperature. The generator further comprises temperature sensor to measure temperature of the reactor.    USE - In a fuel cell (claimed) which is useful for e.g. an independent power generator of large sized buildings, power supply of electric cars and portable power supply.    ADVANTAGE - The hydrogen generator constantly and easily controls the amount of generated hydrogen regardless of the temperature effect of the surrounding environment. The fuel cell comprising the hydrogen generator is small-sized and provides high output.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a fuel cell comprising the hydrogen generator; an electricity generator (10) for generating electric energy by an electrochemical reaction between the hydrogen supplied from the hydrogen generator and oxidizer; a detector (30) for detecting an output current and an output voltage of the electricity generator and outputting a signal of the detected output current and the output voltage; and a controller (40) for controlling the amount of hydrogen generated from the hydrogen generator based on the signal transferred from the detector and controlling the temperature controller based on the temperature detected by the temperature sensor; and    (2) regulating an amount of a chemical reaction in a hydrogen generator involving measuring a temperature of the hydrogen generator; communicating a signal of the measured temperature to a control circuit; determining whether the temperature is at a predetermined temperature range; and decreasing an amount of the chemical reaction between a catalyst and an aqueous solution of chemical hydride when the temperature of the hydrogen generator is higher than the predetermined temperature range.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a fuel cell employing a hydrogen generator.    Electricity generator (10)    Hydrogen generator (20)    Reactor (22)    Temperature controller (24)    Detector (30)    Controller. (40)