A document reading apparatus and method are provided for outputting an image faithful to a document as possible even if the document is accidentally fed in an oblique fashion on the way of a sheet feeding path. For this purpose, a plurality of document end detecting sensors S1 to S3 are disposed on the way of the sheet feeding path 5, and further, a reading controller 20 calculates a skew quantity θ of the document with respect to the sheet feeding path 5 based on a signal output from the document end detecting sensor, thereby adjusting a document reading timing in accordance with the skew quantity.