Example embodiments relate to a sheet amount indicator for use in a sheet-feeding tray. The sheet-feeding tray includes a sheet stacking part having a base plate where sheets are stacked, and the base plate is configured to rise up for feeding of a topmost sheet stacked. The sheet amount indicator includes a viewing part disposed on an outer surface of the sheet stacking part, an indicator member configured to move as seen through the viewing part, a cooperative mechanism configured to move in accordance with a vertical movement of the base plate, and an amplifying mechanism disposed outside the sheet stacking part and connected to the cooperative mechanism so as to amplify the movement of the cooperative mechanism to transmit the amplified movement to the indicator member.