A photoreceptor unit capable of stabilizing rotation of a photoreceptor drum housed in a housing of the photoreceptor unit without causing a displacement of the photoreceptor drum. The photoreceptor unit is provided with a braking member as a mechanism for stabilizing the rotation of the photoreceptor drum, the braking member being arranged between a part of the photoreceptor drum and a part of the housing or a support shaft for rotatably supporting the photoreceptor drum so as to effect a load in a radial direction throughout the entire circumference of the rotation of the photoreceptor drum.