To provide an image forming device, capable of compacting, and preventing deterioration of image quality due to scattering of toner.

When a sheet P after a toner image is fixed to one surface is reversed to a transfer part 54 again, the sheet passing a first curvature part R1 is guided by a second curvature part R2 to be bent in the opposite direction to the first curvature part R1, so that curling generated in the sheet P when passing the first curvature part R1 is corrected. The radius of curvature of a third curvature part R3 is set in such a way that the quantity of curling generated in the sheet P is small when it is guided through the third curvature part R3 to be sent through the transfer part 54 to a fixing part 55.