Abstract: The thickness of a conductive film formed on a substrate can be measured efficiently at low cost with a film thickness measuring apparatus of the invention, which includes an eddy current coil sensor, disposable at a predetermined position near a conductive film, for generating a predetermined eddy current in the conductive film and for detecting a magnetic field caused by the eddy current. The apparatus also includes a displacement sensor for measuring a displacement between the eddy current coil sensor and the conductive film. The thickness of the conductive film is measured in accordance with a variation in inductance of the eddy current coil sensor and the amount of displacement measured by the displacement sensor.