To accurately electrostatically separating plastic pieces into their types so that prescribed plastic pieces are surely recovered with high purity and high recovery rate.

This device is provided with a box body 16, which surrounds a supply tray 2, a metallic drum electrode 5, a high-voltage electrode 6, a first container 8, and a second container 9, and a heating means 15, which comprises a heat source which is disposed in this box body 16 for heating at least one of the metallic drum electrode 5, the high-voltage electrode 6, and an atmosphere for separation. In this constitution, a current is applied to the heat source 17 to increase the temperature of the inside of the box body 16, thereby PE and PP can be separated from each other with high purity and high recovery rates even in a high humidity atmosphere.