PURPOSE: To monitor the quantities of positive and negative charged particle beams separately and simultaneously by emitting both of the positive and negative charged particle beams while having both of them intersected, and thereby disposing a positive and a negative current measuring mechanism on the orbits of the positive and negative charged particle beams after both of them are intersected.

CONSTITUTION: A device is provided with a mechanism producing positive charged particle beams 1, a mechanism producing negative charged particle beams 2 and with a mechanism emitting the positive charged particle beams 1 and the negative charged particle beams 2 while both of the beams are mutually intersected. The device is also provided with a positive current measuring mechanism 3 and a negative current measuring mechanism 4 which are disposed on the orbits of both of the positive and negative charged particle beams 1 and 2 respectively after both of them are intersected, and with a mechanism bringing targets 5a through 5f at a position where both of the particle beams are intersected. By this constitution, the quantities of the positive and negative particle beams can be separately monitored simultaneously so that both of the positive and negative charged particle beams can accurately be controlled to be simultaneously implanted to each target.