The present invention is provided with a configuration which makes it possible to inhibit contact between an oil (L) and a gas in an oil pan (10a) properly. The oil pan (10a) according to the present invention contains a film (S1) which covers an oil surface (F) of the oil (L) to separate the stored oil (L) and the gas above the oil (L). The film (S1) can float by receiving buoyancy in the oil (L). The film (S1) may be formed of a liquid. The film also may be configured by a film member.