The valve device includes: a valve casing that includes a valve casing main body, in which an inlet flow path, an intermediate flow path, and an outlet flow path are formed, and a lid portion that closes an external opening portion formed in the valve casing main body; an intermediate valve seat portion that is detachable from the valve casing main body; a strainer that extends in a direction connecting the lid portion and the intermediate valve seat portion and is disposed between the lid portion and the intermediate valve seat portion; and an energizing member that is disposed between the strainer and the intermediate valve seat portion and is energized the intermediate valve seat portion toward the valve casing main body. The strainer is disposed with the energizing member pressed toward the valve casing main body.