A developing device may include an auger or an agitator that is capable of supplying toner in a toner accommodation chamber to a developing chamber and is rotatable about an auger axis extending in an axial direction, a transporting gear that is rotatable together with the auger or the agitator, and a moving gear that is in mesh with a coupling gear and is rotatable both counterclockwise and clockwise. The moving gear is movable while being in mesh with the coupling gear between a first position where the moving gear is in mesh with the transporting gear and a second position where the moving gear is out of mesh with the transporting gear. The moving gear moves to the first position when the coupling gear rotates counterclockwise and to the second position when the coupling gear rotates clockwise.