The vibrating quartz oscillator in the viscous-flow gas was observed to compare the pressure (P) dependence between the impedance change (ΔZ) and the frequency change (ΔF). We obtained the ΔZ and the ΔF for Ar, O₂, and Ne gases. Among Ar and O₂ both the ΔZs and the ΔFs had no intersection with each other. However, Ne gas had the intersections with Ar gas with the ΔZ(P) and with O₂ for the ΔF(P). The phenomenon was caused by the Ne property which Ne has smaller mass but larger viscosity compared with Ar and O₂. The ΔZ-ΔF property showed that the property of each gas lied in the viscosity descending order, i.e., Ne, Ar, O₂. The measurement of (ΔZ, ΔF) property could give the viscosity related information.