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.