A multi-cylinder engine wherein a direction in which a crank shaft spans is a front and rear direction and a widthwise direction of a cylinder head (1) perpendicular to the front and rear direction is a lateral direction, the multi-cylinder engine comprising the cylinder head (1) which has one lateral side to which an intake-air distributing passage wall (2) and has the other lateral side to which an exhaust-gas converging passage wall (3), a common rail (10) being arranged around the cylinder head (1). In this multi-cylinder engine, the common rail (10) is arranged immediately lateral of the intake-air distributing passage wall (2), thereby positioning the intake-air distributing passage wall (2) between the cylinder head (1) and the common rail (10). Preferably, an intake-air inlet pipe (11) is made to stand up at an upper portion of the intake-air distributing passage wall (2) and is provided with an intake-air flange portion (12), which is positioned just above the common rail (10).