Water electrolysis system

A water electrolysis system comprising:

• a water electrolysis unit including a water electrolysis device configured to perform water electrolysis;
• a housing that includes therein a space through which air flows, and houses the water electrolysis unit in the space;
• a ventilation device configured to cause the air to flow inside the space;
• a heating device provided on an upstream side of the water electrolysis device in a flow path of the air, and configured to heat the air;
• a ventilation temperature sensor provided above the water electrolysis device in the space;
• a heating temperature sensor provided between the heating device and the water electrolysis device in the flow path;
• and
• a control device configured to control operation of the ventilation device based on ventilation temperature information detected by the ventilation temperature sensor, and also control operation of the heating device based on heating temperature information detected by the heating temperature sensor.