Heating of heavy ions is studied analytically and by means of numerical simulations in the presence of a large-amplitude hydrogen cyclotron wave which is commonly observed on auroral field lines. Both one- and two-dimensional numerical simulations showed a decay instability resulting in strong heating of both the oxygen ions and the hydrogen ions. In particular, detailed results of simulations in two dimensions where E¿B drift plays an important role indicate a much stronger heating of the oxygen ions than that in the one-dimensional simulation. A high-energy tail of the oxygen ions is commonly observed in the perpendicular distribution.