An image forming apparatus comprising: an image bearing member capable of bearing a developer image that is formed by supplying a developer to a latent image formed on a surface thereof; a developer carrying member that is provided to be capable of rotating while carrying the developer, and that supplies the developer to the image bearing member by contacting the image bearing member ; a regulating member that regulates a layer thickness of the developer carried on the developer carrying member; and voltage applying means for applying a voltage to the developer carrying member, the developer carrying member includes a conductive base layer and a surface layer covering the base layer , and characterized in that the image forming apparatus is configured such that in image forming operation of the image forming apparatus VT ρ c d c ≤ q s d c ε c ≤ _ d t ε t is satisfied, wherein a volume resistivity of the surface layer is ρc, a film thickness thereof is dc, and a relative dielectric constant thereof is εc, a surface charge density of the developer on the developer carrying member , the film thickness of which has been regulated by the regulating member , is q/s, a relative dielectric constant thereof is εt, and a layer thickness thereof is dt, a potential difference between a potential Vp on the photosensitive drum when the developer carrying member contacts the photosensitive drum and a development voltage Vdc applied to the photosensitive drum is V, and a time required for the developer to pass through the contact region (N) after entering the contact region (N) as the developer carrying member rotates is T. an image bearing member capable of bearing a developer image that is formed by supplying a developer to a latent image formed on a surface thereof; a developer carrying member that is provided to be capable of rotating while carrying the developer, and that supplies the developer to the image bearing member by contacting the image bearing member ; a regulating member that regulates a layer thickness of the developer carried on the developer carrying member; and voltage applying means for applying a voltage to the developer carrying member, the developer carrying member includes a conductive base layer and a surface layer covering the base layer , and characterized in that the image forming apparatus is configured such that in image forming operation of the image forming apparatus VT ρ c d c ≤ q s d c ε c ≤ _ d t ε t is satisfied, wherein a volume resistivity of the surface layer is ρc, a film thickness thereof is dc, and a relative dielectric constant thereof is εc, a surface charge density of the developer on the developer carrying member , the film thickness of which has been regulated by the regulating member , is q/s, a relative dielectric constant thereof is εt, and a layer thickness thereof is dt, a potential difference between a potential Vp on the photosensitive drum when the developer carrying member contacts the photosensitive drum and a development voltage Vdc applied to the photosensitive drum is V, and a time required for the developer to pass through the contact region (N) after entering the contact region (N) as the developer carrying member rotates is T. <EOS>