A throttle control apparatus is configured to be capable of easy assembly. The throttle control apparatus also includes a rotor and an intermediate casing, which surrounds a portion of the rotor. The intermediate casing also houses a position sensor for detecting a rotational angle of the rotor. The rotor and the intermediate casing are both encased in an outer housing, which is configured and adapted to be mounted on a motorcycle handlebar. A return spring, for returning the rotor to an original position, has one end engaged with a first retaining pin on the rotor, and the other end of the return spring is engaged with a second retaining pin on the intermediate casing.