A tandem type photosensitive unit detachably mounted in a main body of an image forming apparatus is provided. The tandem type photosensitive unit includes: a plurality of parallelly arranged photosensitive drums; a first end-side shaft receiving member engaged with a first end portion of each photosensitive drum in the axial direction; a second end-side shaft receiving member engaged with a second end portion, opposite to the first end portion, of each photosensitive drum in the axial direction; a first side plate collectively retaining each first end-side shaft member; and a second side plate collectively retaining each second end-side shaft receiving member.