VALVE DEVICE

A valve device includes: a housing including a peripheral wall, a bottom wall, and a partition wall; and a float valve accommodated in a valve chamber to be able to ascend and descend, thereby opening and closing an opening portion. A slit extends continuously over the peripheral wall and the bottom wall, and a deflectable and deformable elastic piece is formed via the slit. The elastic piece has a free end on the bottom wall, and the free end is provided with a float valve support portion configured to support the float valve.