We present our final results of the charmonium spectrum in quenched QCD on anisotropic lattices. Simulationsare made with the plaquette gauge action and a tadpole improved clover quark action employing ~ = as~at = 3.We calculate the spectrum of S- and P-states and their excitation, and study the scaling behavior of mass splittings.Comparison is made with the experiment and previous lattice results. The issue of hyperfine splitting for differentchoices of the clover coefficients obtained by Klassen is discussed.