This paper deals with the design and fabrication of a quartz-crystal resonator used in a thickness-monitor unit, measuring film thickness in a film-depositing system. A purpose-grown quartz crystal is cut to form the desired wafer. Two gold electrodes are deposited on both surfaces of the wafer to provide electrical contacts. The resonance frequency of the resonator, at room temperature, and the variation of the resonance frequency of the resonator with the temperature are measured. The fabricated resonator is finally used in the thickness-monitor unit of a vacuum coater.