a main frame comprising two parallel horizontal rails extending along one direction, the two parallel horizontal rails comprising an upper left side rail and an upper right side rail;

a guide rail, wherein the guide rail moves along the one direction, the guide rail comprises a first guide rail and a second guide rail, and the first guide rail and the second guide rail are installed parallel to the upper left side rail and the upper right side rail of the main frame;

a rack equipped with a temperature sensor on one side of the rack, wherein the rack holds a number of raw glass portions inside and the temperature sensor measures a temperature of the raw glass portions;

a transport apparatus having a lower part and an upper part, wherein the lower part is coupled with an upper part of the rack and the upper part of the transport apparatus is coupled to the guide rail, and the transport apparatus moves horizontally in the one direction of the guide rail;

a strengthening furnace, wherein the strengthening furnace is formed along a length direction of the main frame on an inner ground of the main frame, and has a strengthening section, wherein the strengthening section strengthens the raw glass portions by spraying a potassium nitrate solution heated to the raw glass portions and maintaining the potassium nitrate solution heated on the raw glass portions for a predetermined time, the strengthening section having a plurality of recovery holes formed in a bottom of the strengthening section;

a cleaning apparatus for cleaning the tempered glass from the strengthening furnace; and

a drying apparatus for drying the tempered glass cleaned from the cleaning apparatus.