An ion implantation device equipped with a high-speed driving device which causes rotation of the a disk that supports semiconductor wafers around it outer periphery. A center position of the disk is the axis of the rotation of the high speed rotation. A low-speed driving device causes relative movement of the disk in a radial direction. The ion implantation device further has a control circuit which calculates the movement speed of the aforementioned low-speed driving device with reference to different spacings between wafers about the outer periphery and the distance from the center of the disk to the ion implantation position, and controls said low speed scan speed so that ions are uniformly implanted into the aforementioned wafers.