An oil pan for an internal combustion engine, comprising: an oil pan main body which includes a flange, a peripheral wall, and a bottom wall, the flange having a rectangular opening and being joined to a lower portion of a body of an internal combustion engine equipped with a crankshaft, the peripheral wall extending downward from an inner edge of the flange, the bottom wall being joined to a lower end of the peripheral wall, wherein: the bottom wall includes a deep bottom portion and a shallow bottom portion, the shallow bottom portion being arranged adjacent the deep bottom portion in a direction in which the crankshaft extends and located at a higher position than the deep bottom portion, the shallow bottom portion being joined to the deep bottom portion through a stepped portion, the shallow bottom portion includes a middle bottom section, a first raised bottom section, and a second raised bottom section, the middle bottom section occupying a central portion of the shallow bottom portion in a direction crossing the crankshaft, the first raised bottom section and the second raised bottom section being arranged on the opposite sides of the middle bottom section in the direction crossing the crankshaft and located at a higher position than the middle bottom section, characterized in that: the oil stored in the oil pan main body lies above the shallow bottom portion as the oil pan main body stores a specified amount of oil, and the first and second raised bottom sections (14E, 14F) of the shallow bottom portion have their upper surfaces (14e, 14f) located below and in the vicinity of the lower level of the oil stored in the oil pan main body, which is the lower limit of the level of the oil kept in the oil pan main body. the bottom wall includes a deep bottom portion and a shallow bottom portion, the shallow bottom portion being arranged adjacent the deep bottom portion in a direction in which the crankshaft extends and located at a higher position than the deep bottom portion, the shallow bottom portion being joined to the deep bottom portion through a stepped portion, the shallow bottom portion includes a middle bottom section, a first raised bottom section, and a second raised bottom section, the middle bottom section occupying a central portion of the shallow bottom portion in a direction crossing the crankshaft, the first raised bottom section and the second raised bottom section being arranged on the opposite sides of the middle bottom section in the direction crossing the crankshaft and located at a higher position than the middle bottom section, characterized in that: the oil stored in the oil pan main body lies above the shallow bottom portion as the oil pan main body stores a specified amount of oil, and the first and second raised bottom sections (14E, 14F) of the shallow bottom portion have their upper surfaces (14e, 14f) located below and in the vicinity of the lower level of the oil stored in the oil pan main body, which is the lower limit of the level of the oil kept in the oil pan main body. the oil stored in the oil pan main body lies above the shallow bottom portion as the oil pan main body stores a specified amount of oil, and the first and second raised bottom sections (14E, 14F) of the shallow bottom portion have their upper surfaces (14e, 14f) located below and in the vicinity of the lower level of the oil stored in the oil pan main body, which is the lower limit of the level of the oil kept in the oil pan main body.