To provide a method and a device to process an implantation surface of a workpiece by colliding an ion onto the implantation surface of the workpiece.

This ion implantation device 10 is equipped with an implantation compartment 12 to insert a workpiece 14, a supporting device 30 to place the workpiece in an inside region with the implantation surface of the workpiece facing the inside region, an optical spectrometer 175 to output optically analyzed data by monitoring ion plasma, and a data storage device to enable adjusting a parameter in accordance with this output, and characteristics of the ion plasma is determined by optical analysis of the plasma using the optical spectrometer. A tool of analysis is executed on a computer by using the database from the data storage device, to determine relative concentration of plasma components.