Abstract: There is provided a valve device including: a housing; and a float valve. The float valve includes a main float, a sub-float held at an upper portion of the main float to be able to ascend and descend by a predetermined distance with respect to the main float, and a sub-float biasing spring disposed between the main float and the sub-float and configured to bias the sub-float upward with respect to the main float. The sub-float includes a spring support portion configured to support an upper end of the sub-float biasing spring and a seal portion that is configured to come into contact with and separate from an opening portion. The main float is movable further upward with respect to the sub-float by compressing the sub-float biasing spring in a state where the float valve ascends and the opening portion is closed by the sub-float.