A pattern measurement method includes: acquiring sectional shapes of a first pattern corresponding to process parameters, respectively; using the acquired sectional shapes to calculate predicted spectral waveforms which would be obtained when light is applied to the first pattern, and adding information on the corresponding process parameters to the calculated predicted spectral waveforms, respectively, to form a waveform library; setting a process parameter to obtain a desired shape, and acquiring an actual spectral waveform of a second pattern actually created from the first pattern using the set process parameter; performing waveform matching between the actual spectral waveform and the predicted spectral waveforms to acquire matching scores for respective waveform matching, and calculating an optimum process parameter providing the maximum matching score; generating an optimum pattern sectional shape corresponding to the optimum process parameter to measure the optimum pattern sectional shape.