A cooking apparatus comprising: a cavity unit having a cooking chamber, a top wall plate with an upper heater hole section, a bottom wall plate with a lower heater hole section, and a rear wall plate with an introduction hole section; a door unit on or over the cavity unit, configured to open and close an opening of the cavity unit; an upper heater unit installed on the top wall plate, configured to supply heat and/or hot air to the cooking chamber through the upper heater hole section; a lower heater unit installed on the bottom wall plate, configured to supply heat and/or hot air to the cooking chamber through the lower heater hole section; a convection heater unit installed on the rear wall plate, configured to supply heat and/or hot air 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/or control an amount of heat supplied to the cooking chamber from the convection heater unit, wherein the introduction hole section comprises: an upper introduction hole section in an upper part of the rear wall plate; and a lower introduction hole section separate from the upper introduction hole section, in a lower part of the rear wall plate, characterized in that the introduction opening and closing unit comprises an upper opening and closing section configured to open and close the upper introduction hole section, wherein the upper opening and closing section comprises: upper rails installed on the rear wall plate; and an upper opening and closing door for opening and closing the upper introduction hole section by being slidingly moved along the upper rails. a cavity unit having a cooking chamber, a top wall plate with an upper heater hole section, a bottom wall plate with a lower heater hole section, and a rear wall plate with an introduction hole section; a door unit on or over the cavity unit, configured to open and close an opening of the cavity unit; an upper heater unit installed on the top wall plate, configured to supply heat and/or hot air to the cooking chamber through the upper heater hole section; a lower heater unit installed on the bottom wall plate, configured to supply heat and/or hot air to the cooking chamber through the lower heater hole section; a convection heater unit installed on the rear wall plate, configured to supply heat and/or hot air 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/or control an amount of heat supplied to the cooking chamber from the convection heater unit, wherein the introduction hole section comprises: an upper introduction hole section in an upper part of the rear wall plate; and a lower introduction hole section separate from the upper introduction hole section, in a lower part of the rear wall plate, characterized in that the introduction opening and closing unit comprises an upper opening and closing section configured to open and close the upper introduction hole section, wherein the upper opening and closing section comprises: upper rails installed on the rear wall plate; and an upper opening and closing door for opening and closing the upper introduction hole section by being slidingly moved along the upper rails.