The mechanism of electrical conduction in PEEK (polyether-ether-ketone) was studied from the results of DC conduction and thermal pulse current (TPC) measurements. The DC conduction current in PEEK films was measured at various electric fields at room temperature. From the results of electric-field dependence, it is thought that the conduction mechanism in PEEK is due to hopping. The TPC spectra, which were obtained under short-circuit conditions after the application of various voltages, show the existence of heterospace charges near the two electrodes. The TPC spectra increase with an increase in the electric field applied. From these results, it is thought that the electrical conduction in PEEK is due to carrier hopping. The carriers reached near the counterelectrode are not easily neutralized and begin to form heterocharges.