A substrate polishing system includes: a polishing machine and a substrate transporter. The polishing machine includes: a lower surface plate to which a substrate is mounted, and an upper surface plate which faces the lower surface plate and polishes the substrate in cooperation with the lower surface plate, the upper surface plate having a larger area than the substrate mounted on the lower surface plate. The substrate transporter is adjacent to the polishing machine and commonly transports the substrate to and from the polishing machine in a first direction, attaches the substrate to the lower surface plate before polishing thereof, and separates from the lower surface plate the substrate after polishing thereof.