Semiconductor chip mounting apparatus 90 is provided with semiconductor chip supply unit 10, semiconductor chip carrier unit 20, lead frame carrier unit 30, sensor unit 60 and a control unit 70. Semiconductor chip carrier unit 20 picks up a semiconductor chip 3 from semiconductor chip supply unit 10 and carries the same to mounting position 50 of lead frame 31 and mounts it on mounting position 50. Sensor unit 60 measures first and second positions of semiconductor chip carrier unit 20 before and during mounting operations, respectively. Control unit 70 compares the first position of semiconductor chip carrier unit 20 with the second one of semiconductor chip carrier unit 20 and calculates position deviations. Control unit 70 further provides position adjustment instructions when the position deviations are greater than a predetermined value thereby to improve the throughput and precision of semiconductor chip mounting apparatus 90.