A cooking apparatus includes a cavity unit having a cooking chamber therein, and a rear wall plate with an introduction hole section therein; a door unit on the cavity unit, configured to open and close an opening of the cavity unit; a convection heater unit on the rear wall plate, configured to generate heat to be supplied to the cooking chamber through the introduction hole section; and an introduction opening and closing unit configured to open and close the introduction hole section and control an amount of heat to be supplied to the cooking chamber.