A developing device usable with an image forming apparatus, which has an improved configuration to allow smooth flow of developer stored therein. The developing device includes a housing in which a developer receiving chamber is defined, a partition to divide the developer receiving chamber into a first developer receiving chamber and a second developer receiving chamber, and a first developer delivery member arranged in the first developer receiving chamber to deliver developer in a first direction. The partition includes at least one opening to communicate the first developer receiving chamber and the second developer receiving chamber with each other, and a shield to block between the first developer receiving chamber and the second developer receiving chamber at an upstream position of the first direction so as to isolate the two developer receiving chambers from each other.