A cylindrical internal surface processing method comprising: forming a cylinder bore in a cylinder block with the cylinder bore having a cylindrical internal surface including an upper section and a lower section; roughening the upper section of the cylindrical internal surface to create a roughened surface such that a radially innermost edge of the roughened surface with respect to a central axis of the cylinder bore has an internal diameter smaller than an internal diameter of the lower section; and depositing a thermally sprayed coating onto the cylindrical internal surface of a base member to cover the upper section and at least a portion of an axial length of the lower section after the roughening of the upper section, characterized by (i) machining the thermally sprayed coating along the lower section to form a tapered portion and a bottommost cylindrical portion such that the tapered portion extends from the cylindrical portion toward the upper section; (ii) wherein machining of the lower section further includes forming the tapered portion such that the tapered portion extends across the thermally sprayed coating and portions of the cylindrical internal surface which do not have the thermally sprayed coating at an axial end of the cylindrical internal surface axially closest to the lower end section with respect to the central axis; (iii) wherein the machining of the thermally sprayed coating further includes removing a low adhesion portion of the lower end of the thermally sprayed coating being removed during a mechanical cutting; and (iv) the machining of the thermally sprayed coating further includes removing a high adhesion portion of the lower end of the thermally sprayed coating adjacent to the low adhesion portion of the thermally sprayed coating; (v) wherein a radially outermost edge of the lower end section of the cylindrical portion has an internal diameter that is larger than an internal diameter of a radially outermost edge of the roughened surface with respect to the central axis. forming a cylinder bore in a cylinder block with the cylinder bore having a cylindrical internal surface including an upper section and a lower section; roughening the upper section of the cylindrical internal surface to create a roughened surface such that a radially innermost edge of the roughened surface with respect to a central axis of the cylinder bore has an internal diameter smaller than an internal diameter of the lower section; and depositing a thermally sprayed coating onto the cylindrical internal surface of a base member to cover the upper section and at least a portion of an axial length of the lower section after the roughening of the upper section, characterized by (i) machining the thermally sprayed coating along the lower section to form a tapered portion and a bottommost cylindrical portion such that the tapered portion extends from the cylindrical portion toward the upper section; (ii) wherein machining of the lower section further includes forming the tapered portion such that the tapered portion extends across the thermally sprayed coating and portions of the cylindrical internal surface which do not have the thermally sprayed coating at an axial end of the cylindrical internal surface axially closest to the lower end section with respect to the central axis; (iii) wherein the machining of the thermally sprayed coating further includes removing a low adhesion portion of the lower end of the thermally sprayed coating being removed during a mechanical cutting; and (iv) the machining of the thermally sprayed coating further includes removing a high adhesion portion of the lower end of the thermally sprayed coating adjacent to the low adhesion portion of the thermally sprayed coating; (v) wherein a radially outermost edge of the lower end section of the cylindrical portion has an internal diameter that is larger than an internal diameter of a radially outermost edge of the roughened surface with respect to the central axis. (i) machining the thermally sprayed coating along the lower section to form a tapered portion and a bottommost cylindrical portion such that the tapered portion extends from the cylindrical portion toward the upper section; (ii) wherein machining of the lower section further includes forming the tapered portion such that the tapered portion extends across the thermally sprayed coating and portions of the cylindrical internal surface which do not have the thermally sprayed coating at an axial end of the cylindrical internal surface axially closest to the lower end section with respect to the central axis; (iii) wherein the machining of the thermally sprayed coating further includes removing a low adhesion portion of the lower end of the thermally sprayed coating being removed during a mechanical cutting; and (iv) the machining of the thermally sprayed coating further includes removing a high adhesion portion of the lower end of the thermally sprayed coating adjacent to the low adhesion portion of the thermally sprayed coating; (v) wherein a radially outermost edge of the lower end section of the cylindrical portion has an internal diameter that is larger than an internal diameter of a radially outermost edge of the roughened surface with respect to the central axis.