A heating apparatus including a side wall heat insulator configured to provide an inner space for receiving a reaction tube, an upper wall heat insulator covering a top portion of the side wall heat insulator, a heat generation part in an inner surface of the side wall heat insulator, and a heat compensating part on a lower surface of the upper wall heat insulator, the heat compensating part including a reflection surface in a first region on the lower surface of the upper wall heat insulator, the first region having a first emissivity less than an emissivity of the upper wall heat insulator may be provided.