The inventive concept relates to a substrate heating unit. The substrate heating unit includes a chuck stage having an inner space defined by a base and sidewalls, a heating unit provided in the inner space of the chuck stage, and a quartz window that covers the inner space of the chuck stage and has an upper surface on which the substrate is placed. The heating unit includes a heating plate having a disk shape with an opening in the center thereof and heating modules installed in respective heating zones on the heating plate that are divided from each other, each heating module having a printed circuit board on which heating light sources emitting light for heating are mounted.