In this paper, we report an investigation using pulsed electroacoustic (PEA) method on electrical breakdown phenomena in a low-density polyethylene (LDPE) film. A space charge distribution and an external circuit current were simultaneously measured up to electrical breakdown in a 100μm thick LDPE film with a semi-conducting electrode under DC voltage. An electric field distribution and conduction current were estimated based on these experiments. An electric field distortion due to a positive charge accumulation was observed at room temperature near the breakdown field. At 60 and 90°, an electric field distortion due to a negative charge was observed but the electric field distortion was not so large even near the breakdown field. The estimated conduction current reached to about 10mA/m2 before the electrical breakdown in each measurements. From obtained results, it is suggested that the LDPE film becomes quasi-conductive for negative charge near the breakdown field, the electrical breakdown is more affected by the conduction current than by the maximum electric field within the LDPE film.