To reduce an oil level of a shallow bottom portion while reducing film vibration of the shallow bottom portion in an oil pan having the shallow bottom portion and a deep bottom portion.

A plurality of belt-shaped recessed curve surfaces 111, 112, 113 extending in the front-back direction (oil flowing direction) are provided on a bottom surface 110 of a shallow bottom portion 11 of an oil pan 1. The adjacent recessed curve surfaces are partitioned by ridge lines 114, 115 where the adjacent recessed curve surfaces intersect with each other. By providing the plurality of recessed curve surfaces on the shallow bottom portion 11, the stiffness of the bottom surface of the shallow bottom portion 11 can be enhanced and the film vibration can be suppressed. Further, since a portion other than the ridge lines of the shallow bottom portion 11 can serve as an oil passage, an area for the oil passage can be sufficiently ensured. Thus, the oil level of the shallow bottom portion can be reduced while reducing the film vibration of the shallow bottom portion in the oil pan having the shallow bottom portion.