Space purification device according to the present disclosure includes hypochlorous acid water generator, mixing bath, hypochlorous acid water supply unit, water supply unit, humidifying purification unit, and control unit. Control unit is configured to, after a humidifying purification operation using the mixture water has finished, perform a first washing operation of causing water supply unit to supply water to electrolytic bath and of causing hypochlorous acid water supply unit to supply water stored in electrolytic bath to mixing bath, without performing the electrolyzing.