A transfer unit includes a first roller, a second roller, a first bearing member, a second bearing member, a roller holder, a first urging member, a second urging member, a first switching cam, a second switching cam, and a driving mechanism. The first and second switching cams have first and second guide holes with which first and second engaging portions formed on the first and second bearing members engage respectively. By rotating the roller holder, one of the first and second rollers is arranged opposite an image carrying member and, by rotating the first and second switching cams to change engaging positions of the first and second engaging portions respectively, the first or second roller is arranged either at a reference position at which it is kept in pressed contact with the image carrying member or at a released position.