A control device of an internal combustion engine determining a target throttle opening degree based on a target intake air amount which can simply and reliably detect any control abnormality is provided. The control device of an internal combustion engine determining a target throttle opening degree based on a target intake amount compares the target intake air amount and an intake air amount measured by an air flow meter to detect a control abnormality. By this control device, it is possible to simply and reliably detect a control abnormality in the process of determination of the target throttle opening degree or control of the throttle valve.