The invention provides a substrate processing device capable of furthest reducing the number of reverse passing parts and reducing the standby time of transporting manipulator to the utmost extent, and a substrate processing method thereof. The reverse passing part (RVPASS2) comprises a third holding mechanism (93) and a fourth holding mechanism (94). The third holding mechanism and the fourth holding mechanism are arranged at longitudinally symmetric positions with a rotary central axis between the two mechanisms, and rotate 180 degrees around the rotary central axis, to replace each other inpositions. The transporting manipulator at the loading side passes a substrate to the third holding mechanism or the fourth holding mechanism at a height position (H4). The substrate with front surface and back surface reversed by the reverse passing part is passed to the transporting manipulator at the unloading side from the third holding mechanism or the fourth holding mechanism at a height position (H3). Before a reversing process on the preceding substrate is finished, the transporting manipulator at the loading side can transport the following substrate.