A cooking appliance, comprising: an oven part comprising a cavity having a cooking space therein; a cooktop part comprising a top plate covering an upper portion of the cavity to form an upper space between the top plate and the cavity , and at least one cooktop heating part at least partially disposed in the upper space ; a rear cover covering rears of the oven part and the cooktop part to form a rear space between the rear cover and the oven part ; an exhaust opening disposed between the cooktop heating part and the rear cover , and formed in a way that passes through the top plate ; and a vent grille covering the exhaust opening in an upper portion of the top plate , wherein an upper end opening is formed between the cavity and the rear cover and opens the rear space upward behind the upper space , the top plate connects to the rear cover while covering the upper space and the upper end opening from above, wherein the top plate , comprising: a main plate disposed in an upper portion of the upper space and covering the upper space from above; and an extension plate extended rearward from the main plate and covering the upper end opening from above, wherein the top plate further comprises a coupling part extended from the extension plate and coupled to the rear cover , characterized in that the main plate and the extension plate connect as the same surface while the main plate , the extension plate , and the coupling part are integrated, and the coupling part extends downward from an end portion of a rear of the extension plate . an oven part comprising a cavity having a cooking space therein; a cooktop part comprising a top plate covering an upper portion of the cavity to form an upper space between the top plate and the cavity , and at least one cooktop heating part at least partially disposed in the upper space ; a rear cover covering rears of the oven part and the cooktop part to form a rear space between the rear cover and the oven part ; an exhaust opening disposed between the cooktop heating part and the rear cover , and formed in a way that passes through the top plate ; and a vent grille covering the exhaust opening in an upper portion of the top plate , wherein an upper end opening is formed between the cavity and the rear cover and opens the rear space upward behind the upper space , the top plate connects to the rear cover while covering the upper space and the upper end opening from above, wherein the top plate , comprising: a main plate disposed in an upper portion of the upper space and covering the upper space from above; and an extension plate extended rearward from the main plate and covering the upper end opening from above, wherein the top plate further comprises a coupling part extended from the extension plate and coupled to the rear cover , characterized in that the main plate and the extension plate connect as the same surface while the main plate , the extension plate , and the coupling part are integrated, and the coupling part extends downward from an end portion of a rear of the extension plate . a main plate disposed in an upper portion of the upper space and covering the upper space from above; and an extension plate extended rearward from the main plate and covering the upper end opening from above, wherein the top plate further comprises a coupling part extended from the extension plate and coupled to the rear cover , characterized in that the main plate and the extension plate connect as the same surface while the main plate , the extension plate , and the coupling part are integrated, and the coupling part extends downward from an end portion of a rear of the extension plate . <EOS>