A device for aligning a substrate and a mask, and a method using the same, where the device includes aligning marks in unused portions of the substrate and the mask, a sensing unit for determining overlap of the aligning marks when the substrate is aligned with the mask, and a control unit for controlling an aligning process to be repeated on the basis of data sensed and determined by the sensing unit. The sensing unit may include a camera positioned in photographic range to determine any alignment error in the alignment marks. According to another embodiment of the present invention, the alignment error between the substrate and the mask is sensed to determine whether it is acceptable or not. When the alignment error is unacceptable, the operations for aligning the substrate with the mask are repeated until the alignment error is acceptable.