An engine control apparatus for a motorcycle capable of detecting an abnormality such that there is no change in vehicle behavior even when the abnormality is brought about. A control CPU controls injection and ignition of an engine and a throttle valve. A monitor CPU detects an abnormality of the engine control apparatus. The control CPU calculates a fuel injection amount, an ignition timing, and an opening degree of the throttle valve necessary for controlling the engine and executes a predetermined engine control. The monitor CPU detects the abnormality of the engine control apparatus. A comparison of control values to detect the abnormality by the monitor CPU is executed by a detection interval equal to or smaller than 10 ms.