An auxiliary device for an articulator includes a base and at least an adjusting structure. The base is provided for positioning an articulator, and the adjusting structure is disposed on the base. The adjusting structure includes a first ball joint, a second ball joint and a connecting assembly. The first ball joint is connected to the base, and the two ends of the connecting assembly are connected to the first ball joint and the second ball joint, respectively. The adjusting structure is moved relatively to the articulator by the movement of at least one of the first ball joint and the second ball joint, thereby adjusting the position of a dental cast disposed on the articulator. The auxiliary device is advantageous for conveniently adjusting the dental cast disposed on the articulator and accelerating the process of the preoperative planning.
