A driven roller unit and a paper feeding device are provided. The paper feeding device includes a frame, the driven roller unit and a driving roller. The frame has a dome concave. The driven roller unit has an omnidirectional ball, wherein the omnidirectional ball is in the dome concave. The driving roller is disposed above the frame and the driven roller unit. When the driving roller presses on the driven roller unit, an angle included by the driving roller and the driven roller unit is adjusted due to the rotation of the omnidirectional ball relative to the dome concave, and therefore the force applied on the driven roller unit is uniform.