A wafer basket station includes a semiconductor wafer basket containing therein a number of semiconductor wafers and an elevating device which raises and lowers the wafer basket to bring a desired wafer in its taken out height. A wafer detecting device is formed with a transmission type optical sensor disposed inclined so that the optical axis thereof passes a center of a semiconductor wafer at the desired height, but not to pass adjacent wafers of the semiconductor wafer. The elevating device o...








