The quartz crystal microbalance (QCM) is a quartz crystal plate resonator for measuring a minute mass in terms of the resonant frequency change. In some applications, an adsorbing layer must be formed on the resonator surface, which adsorbs the material whose mass is measured. This layer affects not only the resonant frequency but also its damping as it is viscoelastic. Its presence can not simply be ignored but should be included in the modeling. In our previous work, the algorithm to

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... ize the viscoelastic layer's properties was developed, in which the multiple resonant frequencies and the corresponding resonant resistances were considered including the overtone operation of the quartz crystal plate [1]. It is unrealistic however to assume that the layer's properties are unchanged for such a wide frequency range. In the present paper, no overtone resonance is considered. Mass of the adsorbed material and the thickness of the viscoelastic layer are identified by means of the Newton's method.