An engine controlling apparatus is provided in which a stable limp-home drive is possible even if an open breakdown of a throttle valve occurs. The apparatus includes a throttle breakdown detecting unit S1 for detecting the breakdown in a throttle controlling system including the throttle valve and a throttle opening degree sensor, a throttle power source interrupting unit S2 for interrupting a power source supply to a throttle actuator in the case where the breakdown in the throttle controlling system is detected, and a predetermined operational condition detecting unit S3 for detecting a shift of the operational condition to a predetermined operational condition corresponding to a fully closed condition of the throttle valve in operation of the throttle power source interrupting unit. A bypass controlling unit S4 opens the bypass valve to feed the air to the engine at the time when the predetermined operational condition is detected in operation of the throttle power source interrupting unit.