This chassis (2) is made of a clad material in which a first layer (21) made of austenite stainless steel, a second layer (22) made of Cu or a Cu alloy, stacked on the first layer, and a third layer (23) made of austenite stainless steel, stacked on the side of the second layer opposite to the first layer are roll-bonded to each other, and the thickness of the second layer is at least 15% of the thickness of the clad material.