An image forming apparatus comprising: an image bearing member; a developer bearing member bearing a developer including a toner and a carrier for developing an electrostatic image formed on the image bearing member with the developer; and a control means configured to control an application of an alternate voltage to the developer bearing member to form an alternate electric field between the developer bearing member and the image bearing member, and characterized in that the control means is configured to control the voltage application during a development process, such that a first voltage is applied to form an electric field intensity Eb decreasing an initial resistivity of the carrier to a first resistivity pb of the carrier to move the toner from the developer bearing member to the image bearing member and such that a second voltage is applied to form an electric field intensity Ed increasing the first resistivity pb of the carrier to a second resistivity pd of the carrier, which is smaller as the initial resistivity of the carrier, in order to keep the toner on the image bearing member, wherein in a semi-logarithmic graph, in which an abscissa axis represents an electric field intensity to be applied to the carrier and an ordinate axis represents the resistivity of the carrier on a logarithmic scale, the electric field intensities Eb, Ed are: Eb = Vp 1 − VL / D Ed = Vp 2 − VL / D (where: VL is a potential of the electrostatic image for obtaining the highest density; Vp1, of peak potentials of the alternate voltage, is a peak potential providing such a potential difference as to move the toner toward the image bearing member with respect to the VL potential; Vp2, of peak potentials of the alternate voltage, is a peak potential providing such a potential difference as to move the toner toward the developer bearing member with respect to the VL potential; and D is the closest distance [m] between the image bearing member and the developer bearing member), and a gradient at Ed is K1, and a gradient at Eb is K2, wherein K1 and K2 satisfy 0 ≥ K1 > K2; and the first resistivity pb of the carrier at the electric field intensity Eb satisfies 1.1×10 6 × e n < pb < 6.0×10 7 [Ω·m] (where: e is the base of natural logarithms; and n = 4 × Eb × 10 -7). an image bearing member; a developer bearing member bearing a developer including a toner and a carrier for developing an electrostatic image formed on the image bearing member with the developer; and a control means configured to control an application of an alternate voltage to the developer bearing member to form an alternate electric field between the developer bearing member and the image bearing member, and (where: VL is a potential of the electrostatic image for obtaining the highest density; Vp1, of peak potentials of the alternate voltage, is a peak potential providing such a potential difference as to move the toner toward the image bearing member with respect to the VL potential; Vp2, of peak potentials of the alternate voltage, is a peak potential providing such a potential difference as to move the toner toward the developer bearing member with respect to the VL potential; and D is the closest distance [m] between the image bearing member and the developer bearing member), and a gradient at Ed is K1, and a gradient at Eb is K2, wherein K1 and K2 satisfy 0 ≥ K1 > K2; and the first resistivity pb of the carrier at the electric field intensity Eb satisfies 1.1×10 6 × e n < pb < 6.0×10 7 [Ω·m] (where: e is the base of natural logarithms; and n = 4 × Eb × 10 -7).