A sheet input module includes: a tray; a support plate pivotally disposed on the tray to form a first included angle with the tray, wherein the support plate supports multiple sheets; and a sheet-stopper structure being pivotally disposed on the tray and providing a stopping function for the sheets. In an interlocking mode, the sheet-stopper structure is driven by the support plate according to a change of the first included angle and rotated relatively to the tray to adjust a second included angle between a stopping surface of the sheet-stopper structure and the sheets. A printing device using the sheet input module is also provided.