a rotating member that delivers a developer to an image holding body while rotating, and has a minimum distance with a housing at a portion from delivery of the developer to the image holding body to release of the developer as viewed in an axial direction of the rotation;

a supply member that extends in the axial direction, is disposed diagonally below the rotating member as viewed from the axial direction, and transports the developer while rotating to supply the developer to the rotating member; and

a pair of flow path walls that are disposed above the supply member and sandwich a flow path connecting from an inside to an outside of the housing in an upward-downward direction, the flow path having a first flow path width of an inner flow path opening on an inner side of the housing in the flow path as viewed from the axial direction equal to or larger than the minimum distance, and a second flow path width of an outer flow path opening on an outer side of the housing in the flow path as viewed from the axial direction larger than the first flow path width, wherein the inner flow path opening is a portion at which a distance between the pair of flow path walls is narrowest in the flow path such that the first flow path width is a narrowest width of the flow path,

wherein as viewed from the axial direction, one of the flow path walls is configured to include a projecting portion projecting toward the other of the flow path walls,

wherein a lower surface of the flow path is configured with the one of the flow path walls, and the projecting portion is provided at a portion of the one of the flow path walls forming the outer flow path opening,

wherein a flat surface facing a flow path side is formed on the projecting portion provided at the portion forming the outer flow path opening, and as viewed from the axial direction, an upper end of the flat surface is disposed on the flow path side in a horizontal direction with respect to a lower end of the flat surface.