An engine E of the present invention comprises a valve body 53 configured to open and close ports 0A and 20B formed in a cylinder head 20, a drive cam mechanism 50A operable in association with a crankshaft by a driving power transmission mechanism 28, a pivot cam mechanism 48 which is configured to be pivoted according to movement of the drive cam mechanism 50A to cause the valve body 53 to open and close and is configured to change a pivot state to change a lift characteristic of the valve; and a servo motor 73 configured to change the pivot state of the pivot cam mechanism 48, wherein the servo motor 73 is positioned at one end portion of the pivot cam mechanism 48 such that the servo motor 73 is distant from the driving power transmission mechanism 28.