To provide an implantation device for ion implantation of high current ions into a specimen having a wide area, with which the end station can be embodied in a simple structure and mass separation can be well made with a high through-put.

A band-shaped ion beam 2 of one-dimensional spread is produced by an ion source 1 and deflected for scanning one-dimensionally by two magnetic field octapolar deflectors 3 and 6 in the direction perpendicular to the band, and a slit plate 9 is reciprocated in front of a specimen synchronously with the scan. Only ions of the desired mass number pass through tan a perture 10 in the plate 9 and are implanted into the specimen. Other ions having different mass numbers run against the plate surface or are led into a Faraday cup 12. The spatial distribution of ion beam and temporal change are known by the Faraday cup 12. Because the magnetic field octapolar deflectors 3 and 6 mass separating effect, neutral beams and other beams having different masses do not reach the specimen. As the specimen is in a standstill, the end station can be embodied in a simple structure.