The method for manufacturing large three-dimensional objects of the present invention comprises the following steps: obtaining a three-dimensional shape data for a three-dimensional target object; converting the three-dimensional shape data into a size needed for manufacturing; transforming the size-converted data into a "shell" data (i.e., data of a hallow target object having a cavity therein); dividing the "shell" data into shell segments of such a size that can be manufactured by a rapid prototyping apparatus; prototyping each of the "shell" segments by a rapid prototyping apparatus to manufacture each of prototyped parts; assembling the prototyped parts to produce a prototype of the target three-dimensional shape object.