Abstract: Intercomparison of measurements for the thickness of ultra thin sources anddeposited foils prepared by vacuum evaporation method has been made by meansof the gravimetric, the electron spectrometric analysis and the backscatteringmethods respectively. The results agree with the values obtained with the quartz-crystal micro-balance of Model SF-3. It is proved then that quartz-crystalmicro-balance of Model SF-3 is a reliable tool for the thickness measurements ofultra thin sources and deposited foils prepared with the vacuum evaporationtechnique.