A transfer device and an image forming apparatus having the same are provided. Shapes of cam profiles of first cam members and second cam members controlling movement of first slider members moving a first transfer roller corresponding to a black developer, and second slider members moving a second transfer roller corresponding to a color developer. Times are different as when movement of the first slider members is completed and when movement of the second slider members is completed in mode conversion among a ready mode, a mono mode and a color mode, and thus a driving load generated when the first and second cam members are rotated is reduced, non-uniformity of the rotating speeds of the first and second cam members is reduced, and problems generated due to non-uniform rotating speeds of the cam members are reduced.