PURPOSE: To prevent a port core from floating in casting a cylinder head, and to form a valve guide hole as a hole as cast during the casting.

CONSTITUTION: Core print parts 5a, 5b at an air intake port inlet part and an air exhaust port outlet part of an integrated air intake and exhaust port cores 5 are fitted in a recessed part of a base core 3, and rod-shaped valve guide cores 8 to press a head part of a bent part of the air intake and exhaust port cores are provided on an upper lid core 7. During the casting, the buoyancy of the molten metal is applied to the air intake/exhaust port cores 5, but the head parts of the bent parts of the air intake/exhaust port cores are pressed by the valve guide cores 8, and the tip part of the air intake/exhaust port cores 5 is not afloat. Cavity is formed in the casting by the respective cores, and a valve guide hole continuous to the respective air intake/exhaust port is formed.