A scanner with a simplified document feeding path is provided for scanning a document. The scanner includes a paper path, a conveying mechanism, an optical module and a scan window. The conveying mechanism conveys the document along the paper path. The optical module, rotatably disposed, captures an image of the document conveyed to a first position and a second position in the paper path, wherein the optical module captures a front-side image of the document at the first position and a back-side image of the document at the second position. The scan window, mounted on the optical module, is turned toward the first position and the second position as the optical module rotates, and the optical module captures the image of the document through the scan window.