A two-valve engine comprising: a crankshaft; a piston part coupled to the crankshaft; a cylinder part configured to cooperate with the piston part to define a combustion chamber, the cylinder part including a cylinder head part and a cylinder body part, the cylinder head part having one intake port and one exhaust port, the one intake port communicating with an intake passage and configured to be opened and closed by an intake valve, the one exhaust port communicating with an exhaust passage and configured to be opened and closed by an exhaust valve, the cylinder body part having a cylinder bore in which the piston part is housed; a fuel injector part that injects a fuel to the intake passage; and an ignition device, the combustion chamber being divided into a first region and a second region by a straight line passing through a center of the intake port and a center of the exhaust port, when viewed in the direction of a central axis line of the cylinder bore, the ignition device being arranged in the first region and not on the straight line passing through the center of the intake port and the center of the exhaust port, and the combustion chamber having a non-squish region that is provided in at least a part of a peripheral region of the combustion chamber with respect to the radial direction of the cylinder bore, the non-squish region being a region where, of the cylinder head part and the piston part, at least the cylinder head part is not provided with a raised portion for producing a squish effect, and where substantially no step is provided in a region where an inside upper surface of the cylinder head part and an inner circumferential surface of the cylinder body part are adjacent to and continuous with each other, characterized in that the intake passage is arranged such that the second region where the ignition device is not arranged and the non-squish region are located on a straight line that is an extension of a center line of the intake passage from the center of the intake port, when viewed in the direction of the central axis line of the cylinder bore, and the two-valve engine comprises a rolling bearing configured to support the crankshaft. a crankshaft; a piston part coupled to the crankshaft; a cylinder part configured to cooperate with the piston part to define a combustion chamber, the cylinder part including a cylinder head part and a cylinder body part, the cylinder head part having one intake port and one exhaust port, the one intake port communicating with an intake passage and configured to be opened and closed by an intake valve, the one exhaust port communicating with an exhaust passage and configured to be opened and closed by an exhaust valve, the cylinder body part having a cylinder bore in which the piston part is housed; a fuel injector part that injects a fuel to the intake passage; and an ignition device, the combustion chamber being divided into a first region and a second region by a straight line passing through a center of the intake port and a center of the exhaust port, when viewed in the direction of a central axis line of the cylinder bore, the ignition device being arranged in the first region and not on the straight line passing through the center of the intake port and the center of the exhaust port, and the combustion chamber having a non-squish region that is provided in at least a part of a peripheral region of the combustion chamber with respect to the radial direction of the cylinder bore, the non-squish region being a region where, of the cylinder head part and the piston part, at least the cylinder head part is not provided with a raised portion for producing a squish effect, and where substantially no step is provided in a region where an inside upper surface of the cylinder head part and an inner circumferential surface of the cylinder body part are adjacent to and continuous with each other, characterized in that the intake passage is arranged such that the second region where the ignition device is not arranged and the non-squish region are located on a straight line that is an extension of a center line of the intake passage from the center of the intake port, when viewed in the direction of the central axis line of the cylinder bore, and the two-valve engine comprises a rolling bearing configured to support the crankshaft.