a photosensitive member unit provided with a photosensitive drum rotatable about a rotational shaft thereof;

a developing unit detachably mounted on the photosensitive member unit, extending in a longitudinal direction along the rotational shaft and configured to develop an electrostatic latent image borne on the photosensitive drum with toner; and

a toner cartridge detachably mounted on the developing unit, extending in the longitudinal direction, configured to accommodate the toner and discharge the toner through an opening portion,

wherein the toner cartridge is provided with a holder including a protruding portion on an end side thereof with respect to the longitudinal direction,

wherein the developing unit is provided with a rotatable lift member on an end side thereof with respect to the longitudinal direction,

wherein, in a mounted state in which the toner cartridge is mounted on the developing unit, the toner cartridge is maintained in the mounted state by engaging of a first portion of the lift member with the protruding portion, and

wherein the toner cartridge is transited from the mounted state to a lifted state in which the toner cartridge is rotated upward by contacting of a second portion of the lift member to the protruding portion with rotation of the lift member, and

wherein the toner cartridge includes:

a guide portion configured to be guided by the developing unit while the toner cartridge is being mounted on the developing unit in a mounting direction crossing the longitudinal direction,

a first portion including a first chamber, in which the opening portion is provided, and a second chamber which are aligned in a first direction perpendicular to the longitudinal direction, the first portion including a partition wall partitioning between the first chamber and the second chamber, and

a second portion aligned with the first portion in the longitudinal direction and through which the first chamber of the first portion communicates with the second chamber of the first portion.