A substrate carrying mechanism includes: a base; a substrate holding member placed on the base and capable of holding a substrate and of being advanced and retracted relative to the base; four or more detecting units respectively for detecting different parts of the edge of a substrate held by the substrate holding member when the substrate holding member holding a substrate is retracted; and a controller that determines whether or not a notch formed in the edge of the substrate has been detected by one of the detecting units, on the basis of measurements measured by the four or more detecting units and corrects an error in a transfer position where the substrate is to be transferred to the succeeding processing unit on the basis of measurements measured by the detecting units excluding the one detecting unit that has detected the notch of the substrate.