Disclosed is an apparatus for processing substrate which prevents a plasma discharge from being transferred to a substrate so as to minimize damages on the substrate and also minimize deterioration in quality of a thin film deposited on the substrate, wherein the apparatus may include a process chamber for providing a reaction space, and a gas distribution module for dissociating processing gas by the use of plasma, and distributing the dissociated processing gas onto a substrate, wherein the gas distribution module may include a lower frame having a plurality of electrode inserting portions, an upper frame having a plurality of protruding electrodes and processing gas distribution holes, and an insulating plate having a plurality of electrode penetrating portions.