A developer conveying apparatus includes a developer housing portion, a first spiral feeder, a second spiral feeder, a driving unit, an operation control unit, and a sensor. The first spiral feeder and the second spiral feeder each include a hollow spiral member and rib members. The hollow spiral member is spirally formed and internally has a space. The rib members run in a first direction and bridge spiral pieces constituting the spiral member. The operation control unit causes: the driving unit to change the rotation speed of the first spiral feeder and the second spiral feeder according to a printing linear speed of an image forming part; and the driving unit to change a rotational phase difference between the first spiral feeder and the second spiral feeder referring positions of the rib members to a predetermined rotational phase difference according to the changed rotation speed.