A valve device includes: a casing including a valve chamber; a valve seat disposed in the valve chamber and including a valve hole; a float disposed in the valve chamber and movable in accordance with the amount of drain in the valve chamber to thereby open and close the valve hole; and a support supporting the float in the state of being seated on the valve seat and closing the valve hole. The support includes a base including an opening and having a frame shape, and two float seats disposed in the base, and the float in the state of being seated on the valve seat and closing the valve hole is seated on the two float seats.