An adjustment apparatus for regulating the inclination angle of a spindle motor of an optical disk drive is disclosed. The spindle motor is mounted on a driving circuit board which is mounted in a traverse module. The adjustment apparatus comprises an optic axis regulating tool for containing the traverse module and regulating the inclination angle of the spindle motor. The top surface of the optic axis regulating tool has an opening to expose the spindle motor and a guide rail of the traverse module. A standard plate is placed against on the guide rail, wherein the upper surface of the standard plate is in parallel with the guide rail. A comparable turning wheel is placed to cover the spindle motor, wherein the upper surface of the comparable turning wheel is in parallel with the rotation plane of the spindle motor and a plurality of turbine-like blades are set at the edge of the comparable turning wheel. A gaseous spray nozzle is mounted on the top surface of the optic axis regulating tool and sprays gas out toward the turbine-like blades to drive rotation of the comparable turning wheel and to simultaneously drive rotation of the spindle motor. An autocollimator emits light beams respectively onto the standard plate and the comparable turning wheel and detects the reflective light beams thereof to show the light spots on the screen. An operator can regulate the inclination angle of the spindle motor based on the light spots on the screen.