An image forming apparatus comprising a developing agent storage section including a discharge port for discharging the developing agent; a developing agent mixer configured inside the developing agent storage section to stir the developing agent and move the developing agent towards the discharge port; a motor which rotates at least the developing agent mixer; a motor control section which rotates the motor at either a first speed at which the developing agent is not discharged from the discharge port or a second speed higher than the first speed to discharge the developing agent from the discharge port; and a device control section which controls the motor control section to switch the rotation speed of the motor to the second speed at a timing different from the timing when the developing roller develops the electrostatic latent image.