An engine intake port structure comprising: a cylinder head block comprising an intake port and an exhaust port; a valve unit installed in the cylinder head block and configured to open and close the intake port, a glow plug is installed at a glow plug installation hole that is formed between the intake port and the exhaust port, wherein the intake port is provided in multiple as first and second intake ports (111, 112; 121, 122), wherein at an end corner of the first intake port (111; 121), a first chamfer is formed to be offset (a) with respect to the center of the first intake port (111; 121) and at an end corner of the second intake port (112; 122), a second chamfer is formed to be offset with respect to the center of the second intake port (112; 122), characterized in that an offset direction (D1, D2) of the first and second chamfer (131, 132) is defined as a direction twisted with respect to a base line from a bottom view directly showing a bottom surface of the cylinder head block and the offset direction of the second chamfer is opposite to the offset direction of the first chamfer by 180 degrees, and when the first and second intake ports (111, 112; 121, 122) are opened/closed by the valve unit, the offset directions (D1, D2) allow for the concentration of intake air introduction on a side in which opening widths (c1, c2) of the first and second chamfers (131, 132) are wide at the beginning of an opening stage or at the end of a closing stage, and after the intake ports (111, 112; 121, 122) are opened, opening widths (c1, c2) are formed to be similar at four sides of the valve unit, so that a swirl formed in the intake air is weakened. a cylinder head block comprising an intake port and an exhaust port; a valve unit installed in the cylinder head block and configured to open and close the intake port, a glow plug is installed at a glow plug installation hole that is formed between the intake port and the exhaust port, wherein the intake port is provided in multiple as first and second intake ports (111, 112; 121, 122), wherein at an end corner of the first intake port (111; 121), a first chamfer is formed to be offset (a) with respect to the center of the first intake port (111; 121) and at an end corner of the second intake port (112; 122), a second chamfer is formed to be offset with respect to the center of the second intake port (112; 122), characterized in that an offset direction (D1, D2) of the first and second chamfer (131, 132) is defined as a direction twisted with respect to a base line from a bottom view directly showing a bottom surface of the cylinder head block and the offset direction of the second chamfer is opposite to the offset direction of the first chamfer by 180 degrees, and when the first and second intake ports (111, 112; 121, 122) are opened/closed by the valve unit, the offset directions (D1, D2) allow for the concentration of intake air introduction on a side in which opening widths (c1, c2) of the first and second chamfers (131, 132) are wide at the beginning of an opening stage or at the end of a closing stage, and after the intake ports (111, 112; 121, 122) are opened, opening widths (c1, c2) are formed to be similar at four sides of the valve unit, so that a swirl formed in the intake air is weakened.