The present disclosure relates to a substrate processing device and a substrate processing method, the substrate processing device comprising: a chamber; a substrate support part installed in a processing space inside the chamber so as to enable one or more substrate to rotate; a first gas spraying part for spraying a source gas on a first area of the processing space; a second gas spraying part for spraying, on a second area of the processing space, a reactant gas reacting with the source gas on the second area; and a third gas spraying part for spraying, on a third area, a purge gas for dividing the first area and the second area.