Photoreceptor unit, cartridge, and electrophotographic image forming device

[Problem] To develop a photoreceptor unit. [Solution] Provided is a photoreceptor unit that is attachable to and detachable from a device body of an image forming device having a first body-side helical gear part and a second body-side helical gear part that coaxially rotate, the photoreceptor unit comprising a photoreceptor rotatable about a rotation axis, a first unit-side helical gear part for meshing with the first body-side helical gear part, and a second unit-side helical gear part for meshing with the second body-side helical gear part, the direction of helix of teeth of the second unit-side helical gear part being the same as the direction of helix of teeth of the first unit-side helical gear part, the helix angle of the teeth of the second unit-side helical gear part being larger than the helix angle of the teeth of the first unit-side helical gear part, and the first unit-side helical gear part and the second unit-side helical gear part rotating in a state where the first unit-side helical gear part meshes with the first body-side helical gear part and the second unit-side helical gear part meshes with the second body-side helical gear part.