A water jacket for a cylinder head includes: an upper body disposed at an upper part of the cylinder head inside the cylinder head and through which a coolant flows; a lower body disposed under the upper body inside the cylinder head and through which the coolant flows; and a connector disposed corresponding to a position of an exhaust valve between the upper body and the lower body and integrally connected to the upper body and the lower body. Tt least one penetration hole is formed in the connector along a length direction.