In a pattern forming method, a resist layer disposed on a wafer is exposed by an energy beam. A post-exposure-bake (PEB) is performed on the wafer with the exposed resist layer by using a PEB apparatus. After the PEB, the exposed resist layer is developed, thereby forming a resist pattern. The PEB apparatus includes a baking plate, and the wafer is placed on the baking plate for the PEB when a temperature of the wafer is within a predetermined temperature range.