A maskless exposure device includes an exposure head that includes a digital micro-mirror device configured to reflect a source beam received from an exposure source to a substrate to scan an exposure beam to the substrate, and a system control part configured to control the digital micro-mirror device using a graphic data system file. The graphic data system file includes data of an align-key. The align-key includes an X-align-key that extends in a direction parallel to a scan direction of the exposure head, and has a bar shape in a plan view, and a Y-align-key disposed adjacent to the X-align-key that has a frame shape in a plan view.