To provide a method for machining a bore surface for forming recesses different from those in an intermediate area between an upper area and a lower area, in the upper area of a bore surface including a top dead center, and the lower area thereof including a bottom dead center without requiring shot blasting.

This method for machining the cylinder bore surface includes a surface layer forming step of forming a surface layer with a plurality of recesses distributed to the inner peripheral surface of the cylinder hole of a cylinder block, and a surface roughening step of injecting a high-pressure liquid to the upper area of the inner peripheral surface formed with the surface layer including the top dead center, and the lower area thereof separated from the upper area and including the bottom dead center. A plurality of recesses are previously formed by the surface layer forming step and high-pressure water is injected to the recesses, thereby peripheries of the recesses are intensively shaven to increase diameters of the recesses. In this method, the recesses different from those in the intermediate area are formed in the upper area and lower area of the bore surface without using fine particles such as those in the shot blasting by the formation of the recesses by non-mechanical work and water jet.