To observe the state of a material being cooked in the innermost of a gridiron even in a door closed state through an inspection window of the door by providing a guide of an ascent gradient from the door side toward the innermost side of a heating cabinet at a side face of the cabinet, and placing the gridiron on the guide.

Bearings 21 are provided at both forward ends of a gridiron 23, and protrusion 22 are provided at both rearward ends of the bearings 21. A guide 24 of an ascent gradient from a front side to a rear side is provided at a side face of a heating cabinet 11. The protrusions 22 of the gridiron 23 are slid on the guide 24 of the side face of the cabinet 11. A tray 25 placed on the gridiron 23 is constituted so that a gradient of the gridiron 23 is reduced as the tray 25 placing the gridiron 23 is drawn forward and becomes horizontal when the tray 25 is taken out from the cabinet 11. A movable side of the gridiron 23 is formed as a placing surface of a material to be cooked, and sides fixed to the tray is formed as legs. The protrusion 22 at the rear side of the placing surface is formed by adhering a wire material, bending it or folding an end of the wire In a U shape or the like. A roll is attached to this portion to upgrade its sliding.