To cut cost by shortening the time required for machining mating surfaces of a cylinder body and a cylinder head while adopting a structure capable of being manufactured by a die-casting method.

A cylinder sleeve 11 is provided by means of enveloped-cast and one end 11a of the cylinder sleeve 11 constitutes part of a surface mating with the cylinder head. Molding is performed by the die-casting method while a bore pin 33 of a casting metal mold 6 is fitted into the cylinder sleeve 11. The outer diameter D1 of one end 11a of the cylinder sleeve 11 is formed to be shorter than the outer diameter D2 of another part of the cylinder sleeve 11. An end surface of the one end 11a is formed flat so as to constitute part of the mating surface by machining after casting.