To provide a combination type selector which can separate metal pieces from plastic pieces precisely.

In this selector in which a mixture A of the metal pieces A2 and the plastic pieces A1 is charged on a drum electrode 4, that is irradiated with corona ions from a needle electrode 5 for corona discharge, and is introduced into the electrostatic field between the drum electrode 4 and a plate electrode 9, and by changing a falling locus of the mixture A, the metal pieces A2 are separated from the plastic pieces A1, the needle electrode 5 which forms a corona ion irradiation area having a diameter three times as large as the distance L1 (cm) between the tip part of the needle electrode 5 and the drum electrode 4 on the drum electrode 4 is adopted, a plurality of the tip parts of the needle electrode 5 are arranged in the width direction of the drum electrode 4, the interval X of the tip parts is made 0<X/L1≤3, and a voltage V1 applied between the needle electrode 5 and the drum electrode 4 is made 0.5 (kV/cm)≤V1/L1≤10 (kV/cm).