To provide a cassette transfer system which improves operating efficiency in a semiconductor-manufacturing apparatus.

The cassette transfer system includes a cassette stage 2, a cassette-holding shelf 11, and a cassette transfer mechanism 9, having a cassette transfer machine 5 and a wafer transfer machine 8. The system also includes a cassette-identifying mechanism 16 for identifying the type and mounted position of a cassette mounted on the cassette holding shelf 11 and a control mechanism 12 for controlling the cassette transfer machine 5 and the wafer transfer machine 8, on the basis of information obtained from the cassette-identifying mechanism 16.