In an NMR spectroscopic analyzing method to which the simulated annealing method is applied, each amplitude, decay constant, resonant frequency, and phase of each spectrum component of an FID signal formed by a plurality of spectrum components are used as variables. A perturbation of an estimated value of each variable and a decision of whether the perturbation is accepted or rejected are performed in sequence based on a certain probability depending on a variation amount of a cost function produced from the estimated value. The probability of accepting the perturbation is gradually decreased in the process of repeating the perturbations to obtain estimated values which minimize the cost function.