A substrate processing apparatus includes a process module including a substrate support unit, an inverting unit and a processing unit, and a transfer module, wherein the inverting unit inverts a substrate so that a second surface faces upward, and provides the inverted substrate to the substrate support unit, wherein the processing unit performs a first processing on the second surface of the substrate seated on the substrate support unit, wherein the inverting unit inverts the first processed substrate so that the first surface faces upward, wherein the transfer module takes the substrate with a first surface facing upward out of the process module, and introduces again the substrate with a first surface facing upward into the process module to seat it on the substrate support unit, wherein the processing unit performs a second processing on the first surface of the substrate seated on the substrate support unit.