PURPOSE: To improve machining accuracy of cylinder bore inner surface without requiring equipment that may incur heavy increase in cost.

CONSTITUTION: In honing machining method of cylinder bore 3 inner surface, temperature difference between a high temperature and a low temperature parts of the cylinder bore 3 immediately after finish machining becomes smaller, as compared with the case of no cooling process, by adding the cooling process between rough machining and finish machining, and after leaving it, the difference of shrinkage amount t1 in the lowered temperature condition is not large on the cylinder bore as a whole, while roundness error of the cylinder bore inner surface is little.