A method for measuring a structure based on a spectrum, includes obtaining a first model that includes a first sub-model and a second sub-model following the first sub-model and is trained based on simulation data, generating a second model including a third sub-model identical to the first sub-model, training the second model based on sample spectrum data generated by measuring spectra of sample structures, and estimating, based on the trained second model, the structure from measured spectrum data generated by measuring a spectrum of the structure.