The working model suited for extraoral fabrication has a dental cast connected via a dowel pin to a substrate in a predetermined position, the substrate including a gypsum forming frame and a gypsum portion. The frame has a peripheral wall being open in upper and lower faces, and is fabricated with plastics into a form of having a hollow space in the inner side of the peripheral wall. The gypsum portion has slurry of gypsum hardened which is filled in the hollow space of the frame. The working model is provided with a connection orifice for inserting the dowel pin into the gypsum portion which is filled and formed in the hollow space of the frame, so that the dowel pin is inserted into the connection orifice, thus connecting the dental cast to the substrate.