To surely electrostatically separate and collect plastic fragment pieces by mixing plastic fragment pieces with each other and imparting polarities and amounts of charge to the respective plastic fragment pieces even though a compact frictional electrification device is employed without increasing size of a friction container to increase the number of stirring members or extending time for frictional electrification.

Since a frictional electrification device 10 is provided with first vane members 24, 24 and second vane members 25, 25, plastic fragment pieces 1a, 1b are guided upwards in an interior of an electrification container 22, and stirred while being guided toward a center of the electrification container 22 by the first vane members 24, 24 so that the plastic fragment pieces 1a, 1b are respectively charged with polarities and sufficient amounts of charge by these movements in these two directions. Even if the ratio of the plastic fragment pieces 1a, 1b takes an extreme value or is very near in a series of frictional electrification, the plastic fragment pieces can surely be separated.