A composite separator for separating copper wires A2 and plastic pieces A1 from a mixture A comprising a drum electrode (4), needle-like electrodes (5), and a planar electrode (9). A plurality of needle-like electrodes (5) are arranged to satisfy a relation 0<X/L1</=3, where L1 (cm) is the distance from the forward end of the discharge part (5a) of the needle-like electrode to the drum electrode (4), and X (cm) is the interval between adjacent discharge parts (5a). Each discharge part (5a) is formed such that a corona ion irradiation area being formed on the drum electrode (4) has a diameter three time as long as the distance L1 (cm) and a voltage V1 being applied between the needle-like electrode (5) and the drum electrode (4) is set to satisfy a relation 0.5 (kV/cm) =V1/L1</=10 (kV/cm).
