PURPOSE: To avoid uneven heating of a material to be cooked by providing a suction hole and a blowout hole so as to be opposed to each other to an approximately center on one side in an oven.

CONSTITUTION: A heater 23, a circulating fan 29 and a circulating fan case 28 are arranged above the upper plate 21a in an oven. Suction holes 26 and blowout holes 27 are arranged in a front and a rear part of the upper plate 21a, respectively, so as to be opposed to each other. Hot air 30 heated by a heater 23 in a circulating fan case 28 is blown out from the blowout hole 27. In this case, since the blowout holes 27 are arranged on one side to the material to be cooked 32, regular paths are constituted to pass hot air 30 oven and under the material to be cooked 32, and is sucked into the suction holes 27. Thereby, the material to be cooked 32 is evenly heated by receiving heat from the upper and lower sides thereof. Thus, uneven heating can be prevented.