Thermally stimulated current (TSC) was obtained under a small bias voltage from low‐density polyethylene which had been subjected to a high electric field. Two peaks were found at 50 and 85°C with apparent activation energies of 1.2–1.3 eV and 1.4–1.5 eV, respectively. These peaks were attributable to the drift of thermally released carriers under the external bias field. On comparison of the activation energies obtained from the TSC and the isothermal steady‐state conduction currents, the results were explained successfully with a field‐assisted trapping model where a trap is surrounded by a Coulomb repulsive barrier for electron capture.