A developing device includes a housing, a developing roller, a developer conveyance path, a partition plate, a developer supply port and a developer conveying member. The developer conveying member rotates such that an outer peripheral part thereof moves from top to bottom in a first area between a second shaft portion and the partition plate and moves from bottom to top in a second area between the second shaft portion and the side wall. The developer supply port is obliquely open above the second area. The housing includes a first space formed above the second area of the first conveyance path and a second space formed up to a position higher than the partition plate to communicate with the first conveyance path above the first area of the first conveyance path and communicating with the first space in a horizontal direction.