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.