Understanding of basic physical properties of oxide superconductors is very important for the development of electric power apparatus. A lot of studies have been mainly carried out with DC or AC. However, the frequency dependence of physical properties of oxide superconductors seems not to have been reported except for AC loss. In the present study, a power source was constructed which can supply 10A up to 150kHz. The frequency dependence of the quenching current of bulk and thin-film oxide superconductors was measured using this power source. The results are discussed in terms of heat balance between generation due to hysteresis loss and dissipation to coolant.