A refrigerator with a beverage container cooling device, said cooling device comprising: a case; a cover provided at a front surface of the case; a cool air supply part with a cooling fan configured to supply cool air inside the case; a mixing member which is installed inside the case, the mixing member including: a tray installed inside the case and on which a beverage container can be placed; and a driving part connected to the tray and configured to drive the tray to perform a seesaw motion about a mixing axis to mix a fluid filled in the beverage container; wherein the driving part includes a mixing motor; and a control unit; wherein the driving part comprises: a supporter configured to protrude from a bottom of the case, the tray being connected to an upper end of the supporter by the mixing axis to perform the seesaw motion; a driving link connected to one end of the tray; and the mixing motor which is configured to transmit the driving force to the driving link, wherein the tray comprises: a tray body; a first seating part formed on the tray body so that the beverage container is placed in a lengthwise direction of the tray body; and characterized by a second seating part formed on the tray body in a direction that crosses the first seating part, wherein the control unit is configured to: detect opening and closing of the cover; drive the mixing motor for a predetermined time, when the closing of the cover is detected, and then stop the mixing motor; calculate a load applied to the mixing motor; calculate a weight of a beverage according to the load; calculate a cooling time according to the calculated weight; and drive the cooling fan for the calculated period of cooling time. a case; a cover provided at a front surface of the case; a cool air supply part with a cooling fan configured to supply cool air inside the case; a mixing member which is installed inside the case, the mixing member including: a tray installed inside the case and on which a beverage container can be placed; and a driving part connected to the tray and configured to drive the tray to perform a seesaw motion about a mixing axis to mix a fluid filled in the beverage container; wherein the driving part includes a mixing motor; and a control unit; wherein the driving part comprises: a supporter configured to protrude from a bottom of the case, the tray being connected to an upper end of the supporter by the mixing axis to perform the seesaw motion; a driving link connected to one end of the tray; and the mixing motor which is configured to transmit the driving force to the driving link, a tray installed inside the case and on which a beverage container can be placed; and a driving part connected to the tray and configured to drive the tray to perform a seesaw motion about a mixing axis to mix a fluid filled in the beverage container; wherein the driving part includes a mixing motor; and a control unit; wherein the driving part comprises: a supporter configured to protrude from a bottom of the case, the tray being connected to an upper end of the supporter by the mixing axis to perform the seesaw motion; a driving link connected to one end of the tray; and the mixing motor which is configured to transmit the driving force to the driving link, wherein the tray comprises: a tray body; a first seating part formed on the tray body so that the beverage container is placed in a lengthwise direction of the tray body; and characterized by a second seating part formed on the tray body in a direction that crosses the first seating part, wherein the control unit is configured to: detect opening and closing of the cover; drive the mixing motor for a predetermined time, when the closing of the cover is detected, and then stop the mixing motor; calculate a load applied to the mixing motor; calculate a weight of a beverage according to the load; calculate a cooling time according to the calculated weight; and drive the cooling fan for the calculated period of cooling time. a tray body; a first seating part formed on the tray body so that the beverage container is placed in a lengthwise direction of the tray body; and characterized by a second seating part formed on the tray body in a direction that crosses the first seating part, wherein the control unit is configured to: detect opening and closing of the cover; drive the mixing motor for a predetermined time, when the closing of the cover is detected, and then stop the mixing motor; calculate a load applied to the mixing motor; calculate a weight of a beverage according to the load; calculate a cooling time according to the calculated weight; and drive the cooling fan for the calculated period of cooling time. detect opening and closing of the cover; drive the mixing motor for a predetermined time, when the closing of the cover is detected, and then stop the mixing motor; calculate a load applied to the mixing motor; calculate a weight of a beverage according to the load; calculate a cooling time according to the calculated weight; and drive the cooling fan for the calculated period of cooling time.