A shell-type electrostatic copying apparatus comprising a supporting structure comprised of a lower supporting frame and an upper supporting frame pivotally mounted on the lower supporting frame, a rotating drum rotatably mounted on the supporting structure, a copying paper feed device and a copying paper conveying mechanism including a plurality of lower elements and a plurality of upper elements for conducting a copying paper delivered from the paper feed device to the rotating drum. A conveying unit frame is pivotably mounted on the supporting structure. At least one of the upper elements is mounted on the conveying unit frame, and at least one of the lower elements, on the lower supporting frame. The apparatus also includes a drum unit frame having the rotating drum rotatably mounted thereon. A provisional unit placing means for supporting the drum unit frame movably is provided in the lower supporting frame and/or the conveying unit frame. The drum unit including the drum unit frame is provisionally placed on the provisional unit placing means, and then in the required manner, mounted detachably on the upper supporting frame.