An oven with an improved cooling structure is provided. The oven includes a casing; a cooking chamber located inside the casing and including a top plate forming the top, side plates forming both sides, a back plate forming the back, and a bottom plate forming the bottom; a panel located between the casing and the cooking chamber and spaced apart from the casing to form a fluid path for air to move; and a connection fluid path that guides the movement of air flowing from one side of the panel to the other side of the panel.