A packing is arranged in a manner blocking a gap between with a handle in an edge of an opening of a cooking device body. In a close state of the door, steam generated from an object to be heated in a heating chamber at the time of cooking the object to be heated is prevented by the packing from flowing between an edge and the handle. Hence, it is possible to prevent dews from arising on the handle due to dewing. The packing is equipped with a fixing part installed in a deep end edge of the opening, and a sealing part extending downward from the fixing part and being contactable with a back part of the handle.