The present disclosure relates to a substrate processing apparatus, and more particularly, a substrate processing apparatus that is capable of improving process uniformity on an entire surface of a substrate. The substrate processing apparatus includes a substrate boat in which a substrate is loaded, a reaction tube in which a processing process for the substrate loaded in the substrate boat is performed, a gas supply unit configured to supply a process gas into the reaction tube through an injection nozzle disposed on one side of the reaction tube, a heating unit including a plurality of vertical heating parts, which are disposed along a circumference of the reaction tube outside the reaction tube and configured to divide the circumference to the reaction tube into a plurality of portions so as to independently heat each of the divided portions of the reaction tube, and a control unit configured to control the heating unit.