A wafer transferring device for transferring a wafer to be treated from a wafer supply station of a wafer treating apparatus to a wafer holding member, where the wafer is treated, and from the holding member to a wafer discharge station. The device includes a transfer unit for separately supporting untreated and treated wafers at different heights relative to one another. A carrier unit moves horizontally and reciprocates between the supply and discharge stations and toward and away from the holding member integrally with the transfer unit and is adapted to move up and down the transfer unit.