Analytical expression of the damping ratio and the natural frequency of air-lubricated slideways are presented. By the research, the damping characteristics of air-lubricated slideways is represented by a transfer function which has a first-order formula in the numerator and a third-order formula in the denominator. The third-order denominator of the transfer function which shows damping characteristics of air-lubricated slideways is analytically resolved to factors, a first-order delay system with the fast decay (time constant T3) and a second-order vibration system with damping. Air-lubricated slideway has two time constants T1 and T2 which represent the damping characteristics of the slideway. The damping ratio of the slideway ζ0 is analytically expressed by the time constant T2, the natural frequency of the slideway ωn, and dimensionless number k that is the ratio of T2 and T3 as ζ0 = (1 − k)/(2T2ωn).