A developing device includes: a developing chamber provided with a developing agent-holding body; a first developing agent-accommodating chamber for accommodating a developing agent and arranged below the developing chamber; a first rotating member disposed in the first developing agent-accommodating chamber, elastically deformable and configured to rotate to slidably contact with an inner surface of the first developing agent-accommodating chamber; a second developing agent-accommodating chamber arranged adjacent to the developing chamber and an upper portion of the first developing agent-accommodating chamber, and to which the developing agent in the first developing agent-accommodating chamber is supplied by the first rotating member; and a second rotating member disposed in the second developing agent-accommodating chamber, elastically deformable and configured to rotate to slidably contact with an inner surface of the second developing agent-accommodating chamber and to transport the developing agent in the second developing agent-accommodating chamber toward the developing chamber.