In an image forming apparatus having a toner recycle mechanism employing a two-components developing system, rotational torque of a stirring screw disposed within a developing device and capacity of a recycle toner within the developing device are detected. Where the rotational torque of stirring screw is elevated and the capacity of the recycle toner is increased, control operation for not changing a development bias voltage and lowering rotational speed of the stirring screw is executed. Where the rotational torque of the stirring screw is elevated and the capacity of the recycle toner is not increased, control operation for not changing rotational speed of the stirring screw is executed.