A hydrogen generating apparatus, capable of controlling the amount of hydrogen generation, has an electrolyzer, which is filled with an aqueous electrolyte solution containing hydrogen ions, a first electrode, which is accommodated in the electrolyzer, is submerged in the aqueous electrolyte solution, and generates electrons, a second electrode, which is accommodated in the electrolyzer, is submerged in the aqueous electrolyte solution, and receives the electrons to generate hydrogen, a switch, which is located between the first electrode and the second electrode, a flow rate meter, which measures an amount of hydrogen generation in the second electrode, and a switch controller, which receives a set value, compares the amount of hydrogen generation measured by the flow rate meter with the set value, and controls an on/off status of the switch. The amount of hydrogen generation can be controlled by use of on/off time and/or on/of frequency of the switch.