A sheet-feeding apparatus having simple structure and capable of single-face/double-face scanning/printing sheets at high sheet-feeding efficiency. The sheet-feeding apparatus includes a sheet-feeding path in which sheets can pass through a scanning module and/or a printing module. The sheet-feeding path includes a first passage, a second passage communicating with the first passage and a subsidiary passage formed between the first and second passages. The sheets are selectively fed into and delivered through the first passage, the second passage or the subsidiary passage to be single-face/double-face scanned/printed.