A curling device includes a first curling unit configured to curl a sheet in a first direction and a second curling unit. The second curling unit is for curling a sheet which has passed the first curling unit in a second direction which is opposite to the first direction. The curling device also includes an input unit facilitating manual inputting correction values relating to the curling direction and curling amount to be corrected, and a control unit configured to changeably control the curling amount of each of the first curling unit and the second curling unit, to correspond to the correction values input in the first and second input units.