A cooking appliance comprising a cavity provided with a cooking space therein, and an electronic component space provided outside the cavity , the cooking appliance comprising: a circuit board disposed in the electronic component space ; a supporter configured to space the circuit board from the cavity and support the circuit board ; and a cooling fan configured to generate a flow of cool air passing through the electronic component space through a cool air passage that is an area surrounded by the cavity , the circuit board and the supporter , and a temperature measuring part installed at the supporter and supported by the supporter for measuring a temperature in the cool air passage , the temperature measuring part is disposed between the cavity and the circuit board , wherein the electronic component space is disposed in an upper portion of the cooking space , the supporter comprising a support plate in which the circuit board is mounted onto an upper surface of the support plate , an air guide disposed between the support plate and the upper surface of the cavity , wherein the air guide is disposed in a lateral portion of the circuit board , configured to protrude upward from the cavity and configured to block a lateral portion of the cool air passage , and the temperature measuring part is installed in the air guide , characterized in that a rear plate is disposed at a rear of the circuit board , the rear plate is also disposed between the upper surface of the oven cavity and the support plate , wherein further the rear plate is disposed between the cooling fan and the circuit board , the rear plate forms a blocking wall that blocks between the cooling fan and the circuit board , the rear plate also forms a blocking wall that blocks the rear of a cool air passage , an outlet is formed on the rear plate and penetrates in the front-rear direction, and the cool air passage connects to the outlet . a circuit board disposed in the electronic component space ; a supporter configured to space the circuit board from the cavity and support the circuit board ; and a cooling fan configured to generate a flow of cool air passing through the electronic component space through a cool air passage that is an area surrounded by the cavity , the circuit board and the supporter , and a temperature measuring part installed at the supporter and supported by the supporter for measuring a temperature in the cool air passage , the temperature measuring part is disposed between the cavity and the circuit board , wherein the electronic component space is disposed in an upper portion of the cooking space , the supporter comprising a support plate in which the circuit board is mounted onto an upper surface of the support plate , an air guide disposed between the support plate and the upper surface of the cavity , wherein the air guide is disposed in a lateral portion of the circuit board , configured to protrude upward from the cavity and configured to block a lateral portion of the cool air passage , and the temperature measuring part is installed in the air guide , characterized in that a rear plate is disposed at a rear of the circuit board , the rear plate is also disposed between the upper surface of the oven cavity and the support plate , wherein further the rear plate is disposed between the cooling fan and the circuit board , the rear plate forms a blocking wall that blocks between the cooling fan and the circuit board , the rear plate also forms a blocking wall that blocks the rear of a cool air passage , an outlet is formed on the rear plate and penetrates in the front-rear direction, and the cool air passage connects to the outlet . <EOS>