To provide a cooking apparatus in which the heat of a thermal storage vessel can be effectively utilized, the stability of the temperature of steam to be supplied to a load side can be ensured, and the responsiveness of steam supply to the load side can be secured.

Saturated steam from a heat exchanger 13 is heated by an electric heater 56 to change it into superheated steam. Therefore, steam to be fed to a cooking chamber 14 can be switched between the saturated steam and the superheated steam. When the saturated steam is fed to the cooking chamber 14, the electric heater 56 is turned off, and when the superheated steam is fed to the cooking chamber 14, the electric heater 56 is turned on. The degree of heating by the electric heater 56 is controlled to stabilize the temperature of the superheated steam fed to the cooking chamber 14. Further, the saturated steam of about 150°C in the heat exchanger 13 can be regulated into an arbitrary temperature by the electric heater 56.