As a substrate transportation robot transports an unprocessed substrate W to a substrate transfer position P1, inert gas ejected from a substrate floating head 71 toward the bottom surface of the substrate W floats up the unprocessed substrate W. Driven by an actuator 74, the substrate floating head 71 floating up the unprocessed substrate W then moves down. Upon arrival of the unprocessed substrate W at a substrate processing position P3, a bottom rim portion of the substrate W engages with support pins 3, and as the substrate floating head 71 further moves down, the unprocessed substrate W is transferred to and mounted on the support pins 3. The substrate W is thus positioned at the substrate processing position P3, whereby the bottom rim portion of the substrate W and an opposing surface 5b of a spin base 5 are positioned close to each other and opposed against each other.