A hydrogen producing apparatus according to the present invention includes a reactor containing a hydrogen generating material that reacts with water to generate hydrogen, a water containing vessel, a water supply portion for supplying water from the water containing vessel to the reactor, and a hydrogen outflow portion for leading out hydrogen from the reactor. The reactor and the water containing vessel are attachable to and detachable from the hydrogen producing apparatus. A measuring device for measuring at least one of a hydrogen generation rate from the reactor and a temperature of the reactor is provided. Removal of the reactor is restricted according to a measurement value of the measuring device.