The present invention relates to a cooking appliance. The cooking appliance of the present invention comprises: a frame defining a cooking chamber; a magnetron for generating microwaves in order to cook food received in the cooking chamber; a door connected to the frame so as to open or close the cooking chamber; a gasket disposed in the door and coming in contact with the front portion of the frame in a state where the cooking chamber is closed by the door; and a leakage prevention part disposed in the door and forming a space portion for preventing leakage of the microwaves, wherein the gasket is coupled to the space portion.