[OBJECT] To provide a resin-made oil pan without breakage even when the oil pan strikes against an obstruction.[MEANS TO SOLVE] A bottom wall 2 of an oil pan 1 made of resin material has a front side wall section 5 that is located at a vehicle front side and a rear side wall section 6 that is located at a vehicle rear side with respect to the front side wall section 5 and continues to the front side wall section 5 at a predetermined angle. The front side wall section 5 is set so as to have an inclination so that as a position on the front side wall section 5 gets closer to the vehicle rear side, the position on the front side wall section 5 is located in a lower position in a vehicle up-and-down direction in a state in which the oil pan 1 is secured to a cylinder block mounted on a vehicle. As an external force absorption means, a plurality of lateral ribs 7, each of which has an almost rectangular shape in cross section and extends along a vehicle width direction, are formed on an outer wall surface 5a of the front side wall section 5.