A development apparatus can uniform a toner density by controlling the phase of a toner density fluctuation, and can inhibit fluctuation of the toner density and variation of the toner charge amount. The development apparatus is configured to have a phase control mechanism, which forms a dividing point at a predetermined point (e.g., an opening section provided on a partition plate between two screws) in a flow of a developer within the development apparatus in which a toner density fluctuates spatially due to toner replenishment or toner consumption caused by development, causes the developer divided at the dividing point to pass through different paths (path 1, path 2), thereby shifts a phase of the fluctuation of the toner density within the developer, and thereafter causes thus obtained developers having shifted phases to merge with each other, to perform phase control. The developers spatially having toner density fluctuations are superimposed with shifted phases, thereby a high toner density and a low toner density are averaged so that the toner density is uniformed.