This water supply device (1) is provided with: a water storage tank part (10) that has a water filling port part (14) through which water is poured into the water storage tank part; a water feeding port part (20) for feeding the water stored in the water storage tank part (10); an ultraviolet light source part (40) that is arranged within the water storage tank part (10) and sterilizes the water stored in the water storage tank part (10) by irradiating the water with ultraviolet light; and a UV sensor part (110) that is arranged within the water storage tank part (10) and senses the ultraviolet light emitted from the ultraviolet light source part (40).
