An oil pan separator 132 is disposed so as to divide a space within an oil pan 130 into a first chamber 30a and a second chamber 30b. The oil pan separator 132 has a protrusion 132b formed at a low position in such a manner that a portion of the first chamber 30a protrudes into the second chamber 30b. A protrusion upper-plate 132b1, which serves as an upper end portion of the protrusion 132b, is provided with an oil feed valve 138, which is a one-way valve, for allowing substantially only outflow of oil from the first chamber 30a to the second chamber 30b.