A substrate processing apparatus comprises a transferring device including a grasping section configured to grasp a substrate holder, and a transferring section configured to transfer the substrate holder grasped by the grasping section, and a processing bath for storing a substrate held by the substrate holder so that a surface of the substrate is vertically oriented, and processing the substrate. The grasping section is configured to grasp the substrate holder with a surface of the substrate oriented horizontally. The transferring section is configured to transfer the substrate holder above the processing bath, with the surface of the substrate oriented horizontally.