<p>A method for measuring the thickness of an object is provided. The measuring method comprises: a step of measuring first X-ray reflectivity of a substrate before an object is formed on the substrate; a step of forming the object on the substrate; a step of measuring a second X-ray reflectivity of the substrate after the object is formed; a step of calculating a change amount between the first X-ray reflectivity and the second X-ray reflectivity; and a step of performing fast Fourier transform (FFT) on the calculated change amount.</p>
