Provided are a device and method for polishing a substrate, in which an upper ground surface, a side surface and a lower ground surface of a substrate can be simultaneously polished, and a polishing wheel can be evenly used on the whole so as to be uniformly abraded. A substrate polishing system is to polish a substrate, of which upper edge and a lower edge are polished, and includes: a table, on which the substrate is secured; a spindle provided at the upper portion of a side surface of the table; a polishing wheel formed in the shape of a cylinder and having a rotating shaft mounted perpendicularly to the substrate, so as to polish the substrate with a side surface thereof while rotating by the spindle; and a Z axis movement means for moving the polishing wheel in the vertical direction during the polishing of the substrate.