A control apparatus for an internal combustion engine, includes: a throttle operator; an opening degree detector that detects an operation opening degree of the throttle operator; and an electronic control throttle device that opens and closes a throttle valve disposed in an intake passage of the engine, depending on the operation opening degree detected by the opening degree detector. A throttle valve opening degree of the throttle valve is set to include a zero output throttle opening degree angle at which an output of the engine becomes zero between a low rotational speed region and a high rotational speed region of the engine. The operation opening degree of the throttle operator corresponding to the zero output throttle opening degree angle is set to an opening-side angle ratio that falls within a range between 8% and 12%, both inclusive, with respect to a fully-open opening degree of the throttle operator.