A photoresist baking apparatus is provided. The photoresist baking apparatus comprises a baking chamber including an inlet, an outlet and a cover sealed connected thereon. The cover is applied to guide the hot air entering the baking chamber and includes a heating device for maintaining the temperature of the hot air. The heating device is disposed on the cover for heating the hot air flowing to the cover and maintaining the temperature of the hot air to be consistent when the hot air flowing to the outlet, thereby to prevent from the photoresist volatile condensing and dripping due to decreased temperature after the photoresist volatile contacting the cover and affecting the product quality, and to guarantee the temperature homogeneity inside the baking chamber.