Water electrolysis apparatus

A water electrolysis apparatus that supplies water to a water electrolysis cell and applies a voltage to obtain hydrogen and oxygen, the water electrolysis apparatus comprising:

• a water electrolysis stack in which the water electrolysis cells are laminated;
• a water supply side path including a pipe through which water is supplied to the water electrolysis stack;
• a hydrogen side path including a pipe through which hydrogen generated from the water electrolysis stack is recovered;
• and
• a water recirculation path including a pipe through which water from the hydrogen side path is returned to the water supply side path, wherein:
• in each of the water supply side path and the water recirculation path, a conductivity meter that measures conductivity of water flowing through the pipe, a valve from which water from the pipe is drained, and a controller are provided;
• and
• the controller performs control to drain water from the valve based on a measured value of the conductivity meter.