To provide an attaching structure whereby a working model is easy to attach to and remove from an articulator.

When the base part B of a working model consisting of the base part B and a tooth shape part T1 is molded using a molding frame, a locking member 20 is inserted into the molding frame and molded integrally with the base part B. The locking member 20 has a first recess surrounded by a rim 22 and a second recess surrounded by a rim 23, respectively on the front and back of a U-shaped plate 21, and a plurality of ribs 25 are provided at equal intervals on the back of the U-shaped plate 21. A holding member 50 is attached to the support plate 3a of the support arm 3 of an articulator. The holding member 50 has an engaging projection 52 and a pressure piece 53 which fit respectively into the first and second recesses of the locking member 20, and the ribs 25 provided on the back of the U-shaped plate 21 are locked into locking grooves 55 in the engaging projection 52, whereby the working model can be freely removably attached to the articulator in a single operation.