PURPOSE: To facilitate putting in and out a food to be cooked, facilitate cleaning and enhance the heating efficiency of a cooking tray, by disposing a grill in a chamber when a door is closed, disposing the grill in the exterior of the chamber when the door is opened, folding the grill at the time of placing the cooking tray on a tray rest, and removing the tray from the tray rest at the time of using the grill in a horizontal state.

CONSTITUTION: Grill mount shafts 27, 27 are integrally provided at both side parts of an inner wall surface 14a of a door 14, and ring parts 28a, 28a provided at both side parts of a base end of a grill 28 are turnably engaged to tip parts of the shafts 27, 27 so that the grill 28 can be turned upward and downward with the shafts 27, 27 as a center. When the grill 28 is disposed horizontal, stoppers 28b make contact with the inner wall surface 14a of the door 14, and the rack 28 is fastened in that position. In the case of cooking for which a cooking tray 31 is necessary, the grill 28 is disposed vertical, is set along the inner wall surface 14a of the door 14, an upper end of the grill 28 is held by a grill-holding plate 29, and the tray 31 is supported on tray rests 30. Under this condition, the grill 28 is not disposed between a heater 13 and the tray 31 even when the door 14 is closed, so that the heat emitted from the heater 31 is not absorbed by the grill 28, and the tray 31 is efficiently heated by the heat.