A color printer 1 has a rotary type developing device 30 which rotated by an input gear 46 that receives power from a motor, and a plurality of developing units 13 supported on a frame 28. The plurality of developing units 13 accommodates toner of different colors therein. The frame 28 a first annular gear 29 being configured to be rotated by the input gear 46 and a second ring-shaped annular member 32 having a larger external diameter than the first annular gear 29. The second ring-shaped annular member 32 is disposed adjacent to and on the outer side of the first annular gear and on the same rotational axis.