<p>The relation between the voltage Vp (kV) applied to separation electrodes and the distance L (cm) between the separation electrodes is defined by Vp/L</=10. Even if a spark (20) is produced between the electrodes, namely, between an electrode drum (1) and an electrode plate (2), plastic pieces (3, 3') can be correctly separated with high accuracy without degrading the separation performance.</p>
