A development device includes a developer container, a developer bearer to carry developer to a development range, a partition dividing at least partly the developer container into a supply compartment and a collecting compartment, with an end portion of the partition facing a circumferential surface of the developer bearer, a developer supply member in the supply compartment to supply the developer to the developer bearer, and a developer collecting member in the collecting compartment above the developer supply member, to receive the developer from the developer bearer. An opening is formed in a downstream end portion of the partition in a developer conveyance direction of the developer collecting member to cause the developer to fall to the supply compartment, and a width of the opening in a direction perpendicular to the axial direction increases toward downstream in the developer conveyance direction of the developer collecting member.