Abstract In the present paper, the excitation and damping of the polar motion are treated as a series of stochastic process, and the damping coefficient and constants concerning to the excitation of the polar motion are determined. The damping .coefficient thus determined is 0.320 (year–1), which is very close to that obtained by WALKER and YOUNG. The mean duration of the exciting action of the polar motion is determined as Δt = 6.77 days, and the maximum deviation of the instantaneous axis of the principal moment of inertia of the earth from the mean position is k = 0.″235. The values of these constants are found to be plausible from the geophysical point of view.