When an inner wall of a cylinder head is viewed along an axis of a cylinder, a line that passes through a center of a fuel injection port and a center of a valve opening adjacent to the injection port is defined as a first line, and a line that is perpendicular to the first line is defined as a second line. A notch is formed in a part of the inner wall that defines the injection port. Specifically, when the inner wall is divided into sections by the second line, the notch is located in the section in which the adjacent opening exists. The notch is also displaced from the first line. Therefore, a sufficient thickness of the section corresponding to the valve seats of intake and exhaust valves are easily ensured.