Provided is a developing device that can restrain stress on a developer and improve image quality. This developing device (3a-3d) is provided with: a developing vessel (20) that accommodates the developer, which includes a magnetic carrier and toner; a supply transport screw (23b); a developing roller (31) that carries the developer supplied by the supply transport screw (23b); an ear cutting blade (32) that regulates layer thickness of the developer on the surface of the developing roller (31); and a magnet (50) magnetized on one surface and disposed on the upstream side of the ear cutting blade (32). The magnet (50) is disposed such that a magnetized surface (50a) faces the side of the developing roller (31).