To provide a paper carrying device, an image forming device and an image forming system, capable of restraining an enlargement, while preventing deterioration in image position accuracy.

A paper carrying device 70 includes a carrying-in passage 71a of paper P, a rotary carrying passage 72a, a rotary part 72 of the paper P and a discharge passage 73a of the paper P. The paper P is carried in the rotary carrying passage 72a by the first carrying-in passage 71a, and is discharged by being reversely carried by the first discharge passage 73a after rotating the carrying direction of the paper P by 180°C by the rotary part 72, and is thereby discharged in the same carrying direction by reversing the obverse-reverse of the paper P.