In an accelerating region of a cyclotron an ion makes a large number of turns; thus its tracking requires fast as well as highly accurate computation. Computer code, based on the adaptive time step fourth order Runge Kutta method, has been developed. Accuracy requirement is set simultaneously on the position and momentum calculation. Magnetic fields used as input, have been evaluated in terms of the radial fluctuations of the orbital frequency, i.e. their isochronism. Ion trajectory tracking has been performed for the four test beams: H-, H2 +, 4He+, and 40Ar6+.