PURPOSE: To eliminate uneveness of temp. in a cylinder liner and to uniformize structure by setting chillers in contact with inner circumferential face in the cylinder liner at side part of the bore line direction of bore cores at the time of manufacturing a cast iron-made cylinder block.

CONSTITUTION: The chillers 2 composed of iron series material are set at side part of the line direction of bore core part 4 in the core 1 formed with sand so as to be in contact with the inner circumferential face of cast iron-made cylinder liner 3. Then, after assembling the core 1 into a mold, the molten metal for internal chilling material is poured and filled up, and after solidifying, the mold and core 1 are removed to obtain the cast iron-made cylinder block. Therefore, as the chillers 2 are set at the side part of the bore line direction of bore core parts 4 and the chiller 2 is made to be in contact with the inner circumferential face of cylinder liner 3, unevenness of temp. in the cylinder liner 3 is eliminated and also partial ferritization in the structure is prevented, and the whole cylinder liner 3 can be made to uniform pearlitic structure having high wear resistance.