A developing apparatus includes an organic photo conductor, an OPC frame part to support the organic photo conductor, a developing roller to develop a latent image formed on the organic photo conductor by supplying a developer, a developing roller frame part to support the developing roller, a developer storing part to store the developer and provided with a supplying opening through which the developer is supplied to the developing roller, a spacer removably interposed between the OPC frame part and the developing roller frame part and spacing the OPC frame part from the developing roller frame part such that the organic photo conductor and the developing roller do not contact each other, a leakage preventer removably attached to and sealing the supplying opening, and a connecting part to connect the spacer with the leakage preventer. Thus, the spacer and the leakage preventer are capable of being removed simultaneously.