To provide a sheet stacking device capable of efficiently reducing a temperature of the sheet S without impairing working environment by noise or the like by executing the minimum control output only when a problem of leaving the sheet S at high temperatures can be generated.

A temperature detection sensor 63 for detecting the temperature of the sheet S and a fan motor 61 for air-cooling the sheet S on the stacking tray 18 are provided. When the temperature detected by the temperature detection sensor 63 exceeds a predetermined value (for example, 40°C), the fan motor 61 is operated to reduce the temperature of the sheet S.