An image forming apparatus includes a developer bearing member for transporting developer to an opposing position opposing an image bearing member. Regularly-disposed concave sections are formed on a surface of the developer bearing member. An alternating voltage that includes a first voltage for moving developer from the developer bearing member toward the image bearing member, and a second voltage for moving developer from the image bearing member toward the developer bearing member is applied to the developer bearing member. A cycle period of the alternating voltage is larger than a minimum width of the concave section in a circumferential direction of the developer bearing member divided by a moving velocity of a surface of the rotating developer bearing member.