An image-forming apparatus includes: an exposing unit that irradiates exposing light to an image carrier; a partition member that includes: a light-passing part that allows exposing light irradiated by the exposing unit to pass through the partition member, and that extends in a direction in which the developing unit is attached to or detached from the image-forming apparatus; and a protrusion part that extends along the light-passing part, wherein the light-passing part, the protrusion part, and a part of the partition member located below a supply opening of the developing unit attached to the image-forming apparatus are arranged in an order of the light-passing part, the protrusion part, and the part of the partition member located below the supply opening.