A developing device includes: a rotating member that delivers a developer to a latent image of an image holding body while rotating; a supply member that extends in an axial direction of the rotating member and is disposed diagonally below the rotating member as viewed from the axial direction, transports the developer while rotating, and supplies the developer to the rotating member; and an upper member disposed on an opposite side of the rotating member with respect to a tangent line extending in an upward-downward direction in contact with a portion of the rotating member on a supply member side and above the supply member, as viewed from the axial direction.