Provided is a substrate transferring method which is capable of accurately mounting a substrate at a desired rotation angle. In order to eliminate a misalignment of a wafer W in a rotational direction in a vacuum process chamber, which is caused by a variation in a transfer distance of the wafer W, the wafer W is mounted on a stage while being offset from the center of the stage in a load lock chamber and an angle of rotation of the wafer W with respect to a fork when a transfer arm receives the wafer W is changed.