PURPOSE: To make it possible to keep the sealing function of a liquid gasket when the flange of the oil pan is deflected by a method wherein the connecting surface of the flange of the oil pan is inclined with respect to the connecting surface of a cylinder block so as to provide between the two connecting surfaces a space having a wedge-like cross section to thereby allow the liquid gasket to have a sufficient thickness.

CONSTITUTION: The connecting surface 2a of the flange 2 of the oil pan 1 is inclined with respect to the connecting surface of the cylinder block 5 so that when the oil pan is mounted on the cylinder block 5, the space having a wedge- like cross section is provided between the connecting surfaces of the flange 2 and the cylinder block 5 at a part A between each ajoining two fixing bolts 3. Then the liquid gasket 6 is filled into the space. Consequently, it is possible to allow the liquid gasket to have a sufficient thickness (t) to thereby produce the same effect as would be produced if the flange 2 is provided with a concave section. In other words, even when the flange 2 deflects, the liquid gasket 6 follows the flange 2 without difficulty and the sealing property of the liquid gasket is maintained.