The present invention relates to a document-feeding device. The document-feeding device includes a sheet-feeding channel and a sheet-separating structure. The sheet-separating structure includes a base, a separation pad, a pinch roller, a separation roller and an elastic element. The base is disposed in the sheet-feeding channel. The separation pad is disposed on a surface of the base. The pinch roller is disposed in the base. The separation roller is in contact with the separation pad and the pinch roller. The elastic element is used for supporting the base such that the separation pad and the pinch roller are sustained against the separation roller.