Powder amount detection device, developing apparatus, processing cassette and image forming device

The present invention relates to a powder amount detecting device for detecting powder amount, as well as a developing device provided with the powder amount detecting device, a processing card box and an image forming device. The powder amount detecting device comprises a powder stirring device arranged inside a powder vessel, a driving force transmitting component which transmits driving force to a stirring component for driving the stirring component, a first detecting device which detects the movement of the driving force transmitting component, a second detecting device which detects the movement of the stirring component in the powder stirring device, and a judging device which judges the powder amount inside the powder vessel according to the information gained from the movement detection of the driving force transmitting component by the first detecting device and the information gained from the movement detection of the stirring component by the second detecting device.