A material-removing heater device including: a first terminal portion defining a first electrode; a second terminal portion defining a second electrode; and a heating portion which connects the first terminal portion to the second terminal portion, the heating portion heatable by a flow of electrical current from the first terminal portion to the second terminal portion to remove a portion of material of a display device. The heating portion defines a lower end surface of the material-removing heater device at which the material-removing heater device contacts the material of the display device, the heating portion disposes the lower end surface to have a concave shape, and the heating portion which is heated deforms the lower end surface from the concave shape to have a planar shape.