A rod having a substantially-cylindrical shape with both ends being covered is provided to a lid body, which covers an upper end surface of a case having a bottomed substantially-cylindrical shape, the rod protruding in the case. A first hole is formed in a portion of a side surface of the rod, which is exposed to the inside of the case. Further, an air vent pit (passage) is formed in the lid body, and a second hole is formed in a portion of the side surface of the rod, which is exposed to the inside of the air vent pit. A moving member moves along the rod from a first position at which the moving member does not cover the first hole and a second position at which the moving member covers the first hole.