PURPOSE: To provide a track analyzing method and analyzing device which take a complicated analysis of the track of the smooth restraint system under small initial conditions without difficulties.

CONSTITUTION: The device and method are equipped with an input means 1 which inputs various data of a specific dynamics system, a setting means 2 which sets a differential term and a Lagrangian indeterminate coefficient term of the operation function of the dynamics system on the basis of those inputted data, a generating means 3 which generates simultaneous difference equations of attenuation vibration including the differential term and Lagrangian indeterminate coefficient term, a dividing mess 4 which divides the time of the track into finite elements, an arithmetic means 5 which finds a convergence solution and an indeterminate coefficient on the basis of the simultaneous equations and divided finite elements, and an output means 6 which outputs the convergence solution and indeterminate coefficient data.