A cooking appliance, comprising: an oven unit including a cooking chamber ; a cooktop unit on the oven unit and including at least one cooktop heating unit ; an exhaust vent for discharging air from the cooking appliance; and an electric chamber for accommodating electric parts between the cooking chamber and the cooktop heating unit ; a rear panel forming a rear surface of the cooking appliance; an exhaust duct having a first inlet at the cooking chamber and a first exhaust opening at the exhaust vent for connecting the cooking chamber to the exhaust vent ; a cool air-exhaust duct having a second inlet at the electric chamber and a second exhaust opening at the exhaust vent for connecting the electric chamber to the exhaust vent ; and a guide duct branching from the cool air-exhaust duct and extending along the exhaust duct to the exhaust vent ; characterized in that the guide duct comprising: a first duct unit connected to the cool air-exhaust duct , and a second duct unit being connected to the first duct unit and extending to the exhaust vent , the second duct unit being disposed between the exhaust duct and the rear panel , wherein the second duct unit includes a third exhaust opening that opens the second duct unit toward the exhaust vent and is closer to the exhaust vent than the first exhaust opening , and wherein the third exhaust opening is disposed between the first exhaust opening of the exhaust duct and the rear panel . an oven unit including a cooking chamber ; a cooktop unit on the oven unit and including at least one cooktop heating unit ; an exhaust vent for discharging air from the cooking appliance; and an electric chamber for accommodating electric parts between the cooking chamber and the cooktop heating unit ; a rear panel forming a rear surface of the cooking appliance; an exhaust duct having a first inlet at the cooking chamber and a first exhaust opening at the exhaust vent for connecting the cooking chamber to the exhaust vent ; a cool air-exhaust duct having a second inlet at the electric chamber and a second exhaust opening at the exhaust vent for connecting the electric chamber to the exhaust vent ; and a guide duct branching from the cool air-exhaust duct and extending along the exhaust duct to the exhaust vent ; characterized in that the guide duct comprising: a first duct unit connected to the cool air-exhaust duct , and a second duct unit being connected to the first duct unit and extending to the exhaust vent , the second duct unit being disposed between the exhaust duct and the rear panel , wherein the second duct unit includes a third exhaust opening that opens the second duct unit toward the exhaust vent and is closer to the exhaust vent than the first exhaust opening , and wherein the third exhaust opening is disposed between the first exhaust opening of the exhaust duct and the rear panel . a first duct unit connected to the cool air-exhaust duct , and a second duct unit being connected to the first duct unit and extending to the exhaust vent , the second duct unit being disposed between the exhaust duct and the rear panel , wherein the second duct unit includes a third exhaust opening that opens the second duct unit toward the exhaust vent and is closer to the exhaust vent than the first exhaust opening , and wherein the third exhaust opening is disposed between the first exhaust opening of the exhaust duct and the rear panel . <EOS>