A developing apparatus, a developing method and an image forming apparatus are provided in which reduction in the quantity of development is prevented in the case where a micro particle diameter toner is used. The developing apparatus uses a developer containing a toner and supplies the toner to an image carrier. The developing apparatus includes: a developer housing unit configured to house the developer; a developer carrier in which at least one of magnets provided therein is formed by an electromagnet, and which carries the developer from the developer housing unit toward the image carrier; a developer carrying regulating unit configured to regulate the developer carried by the developer carrier; and an electromagnet driving unit configured to vary a voltage to be applied to the electromagnet.