The present invention relates to an automatic dispenser for a dental impression material, and more specifically, to an automatic dispenser for a dental impression material, configured to quickly and easily replace an impression material cartridge through rapid manual backward movement of a rack while an impression material is discharged at a constant speed through automatic advancement of the rack that pressurizes cylinders, wherein the impression material cartridge including the at least two cylinders which store a silicon base and a hardening material therein respectively is mounted, and when a discharge button provided on a handle unit is pressurized, a motor is driven and automatically pressurizes the cylinders to enable the impression material in which the silicon base and the hardening material are mixed to be discharged. The automatic dispenser for a dental impression material comprises: a shaft provided to be orthogonal to a rotary shaft of the motor and configured to receive a rotational force from the motor； a pinion gear provided on the shaft to be able to freely rotate； a bar-shaped rack coupled to the pinion gear to move and including one end that pressurizes the cylinders； and a clutch module configured to control whether to restrict the pinion gear with respect to the shaft. The clutch module restricts the pinion gear when the dental impression material is discharged and releases restriction of the pinion gear after discharge of the dental impression material is completed so that the rack can quickly move backward to facilitate replacement of the impression material cartridge.본 발명은 치과용 인상재 자동 혼합기에 관한 것으로서, 특히 실린더를 가압하는 랙의 자동 전진을 통해 인상재가 일정한 속도로 토출되면서, 랙의 신속한 수동 후진을 통해 인상재 카트리지를 신속하면서도 용이하게 교체할 수 있도록 실리콘 베이스와 경화제가 각각 내부에 수용되는 적어도 2개의 실린더를 포함하는 인상재 카트리지가 장착되어 손잡이부에 구비된 토출버튼을 가압하면 모터가 구동하며 자동으로 실린더를 가압하여 실리콘 베이스와 경화제가 혼합된 인상재가 토출되는 치과용 인상재 자동 혼합기에 있어서, 상기 모터의 회전축과 직교하도록 구비되며 모터로부터 회전력을 전달받는 샤프트； 상기 샤프트에 자유회전이 가능하도록 구비되는 피니언기어； 바(bar) 형태를 이루며 상기 피니언기어와 결합
