An articulator comprising: a lower jaw fixing member to mount a lower jaw model thereon; and an upper jaw fixing member to mount an upper jaw model thereon, wherein the lower jaw fixing member is vertically foldable with the upper jaw fixing member about a hinge shaft, columns (12 and 22) formed at rear portions of the lower and upper jaw fixing members (10 and 20) has a same length, so that the hinge shaft is formed on a line extending from an occlusal plane (α), thereby operating the lower and upper fixing members (10 and 20) vertically symmetrically to each other about the hinge shaft, and a tangential line (β) of rotation movement is perpendicular to the occlusal plane (α) if the lower jaw model is vertically folded with the upper jaw model about the hinge shaft, characterized in that the lower jaw fixing member has a shaft provided at an upper end of a column formed at a rear portion, the hinge shaft protrudes from both sides of the shaft, and the upper jaw fixing member has rotation support members which are provided at a lower end of a column and provided in a substantially C shape with a groove, such that the upper jaw fixing member is axially coupled with the hinge shaft and detachably coupled with the shaft by a hook formed at a central portion between the rotation support members, that the hook has a push switch, which is provided at a rear portion thereof and has a force of restoration by a spring to elastically operate, such that the hook is detached through one touch scheme, and inclined surfaces (23b and 21b) are formed a front end portion of the hook and a lower end portion of each rotation support member, such that press-fitting is possible, and that the rotation support member has a gradient formed outward from an inner end portion of the groove, such that the hinge shaft is prevented from being locked when the upper jaw fixing member is twisted left or right. a lower jaw fixing member to mount a lower jaw model thereon; and an upper jaw fixing member to mount an upper jaw model thereon, wherein the lower jaw fixing member is vertically foldable with the upper jaw fixing member about a hinge shaft, columns (12 and 22) formed at rear portions of the lower and upper jaw fixing members (10 and 20) has a same length, so that the hinge shaft is formed on a line extending from an occlusal plane (α), thereby operating the lower and upper fixing members (10 and 20) vertically symmetrically to each other about the hinge shaft, and a tangential line (β) of rotation movement is perpendicular to the occlusal plane (α) if the lower jaw model is vertically folded with the upper jaw model about the hinge shaft, characterized in that the lower jaw fixing member has a shaft provided at an upper end of a column formed at a rear portion, the hinge shaft protrudes from both sides of the shaft, and the upper jaw fixing member has rotation support members which are provided at a lower end of a column and provided in a substantially C shape with a groove, such that the upper jaw fixing member is axially coupled with the hinge shaft and detachably coupled with the shaft by a hook formed at a central portion between the rotation support members, that the hook has a push switch, which is provided at a rear portion thereof and has a force of restoration by a spring to elastically operate, such that the hook is detached through one touch scheme, and inclined surfaces (23b and 21b) are formed a front end portion of the hook and a lower end portion of each rotation support member, such that press-fitting is possible, and that the rotation support member has a gradient formed outward from an inner end portion of the groove, such that the hinge shaft is prevented from being locked when the upper jaw fixing member is twisted left or right.