A hydrogen-containing gas supply system includes one or more hydrogen-containing gas suppliers, one or more acquirers, and a controller. The one or more hydrogen-containing gas suppliers supply a hydrogen-containing gas to one or more areas in a building. The one or more acquirers acquire information indicating that a person is present in the one or more areas. When it is determined that a person is present in a certain area of the one or more areas in accordance with the information acquired by the acquirers, the controller causes at least one of the one or more hydrogen-containing gas suppliers to supply the hydrogen-containing gas to the certain area.
