We performed magnetic torque measurements on the heavy fermion system CePd2Si2 in fields up to 28 T and temperatures down to 40 mK to study the de Haas–van Alphen (dHvA) effect. Six different dHvA frequencies were detected when the magnetic field is applied in the basal plane. The corresponding effective masses vary from 6m0 to 23m0: The angular dependence of the dHvA frequencies is generally consistent with the result of the theoretical band structure calculations performed for itinerant f-electrons. One of the dHvA frequencies is split into two close satellites, which most likely originate from the up and down spin bands. Their effective masses are found to differ by a factor of 2, and seem to be field-dependent. This unusual spin-splitting gives rise to an apparent anomalous field dependence of the effective mass obtained from the experiment.