There is provided a method of manufacturing a semiconductor device having a TFT with sufficient characteristics and little fluctuation by accurately controlling the addition amount of impurity ions to the semiconductor layer using an ion doping device. Each lateral frame unit includes a pivot connection seat, a pair of support rods, each having a top rod end pivoted to the pivot connection seat, and a pair of top rods, each having an inner rod end pivoted to the pivot connection seat. A separately controlled motor operates each half of the magazine pressure control.