A developing cartridge includes: a housing; a developing roller rotatable about an axis extending in an axial direction; a first helical gear and a second helical gear positioned at an outer surface of the housing; a cover covering part of the second helical gear; and an engaging member movable with the second helical gear. The second helical gear meshes with the first helical gear and is rotatable in first and second rotational directions. The second helical gear is movable in the axial direction between a first position and a second position farther away from the outer surface than the first position. The second helical gear rotates in the first rotational direction to move to the first position. The second helical gear rotates in the second rotational direction to move to the second position whereby the engaging member engages part of the cover to terminate rotation of the second helical gear.