A liquid-retainable device includes a device body capable of accommodating a liquid, a first ventilation part, a second ventilation part, a partition part, and a humidification filter. The first ventilation part includes a first hole passing through a wall surface of the device body, and being configured to introduce air. The second ventilation part includes a second hole passing through the wall surface of the device body, and being configured to let out the air. The partition part divides an interior of the device body into a first region, which is a region for accommodating the liquid, and a second region, which is a region for forming an air flow path between the first ventilation part and the second ventilation part. The humidification filter is arranged so as to extend from the first region to the second region.