An aluminum bonding alloy is an Ni—Mg alloy for bonding aluminum and a non-aluminum metal selected from steel, copper, nickel or titanium. The Ni—Mg alloy consists essentially of 0.08-0.90 mass % Mg, and the balance of Ni and inevitable impurities. A clad material includes a non-aluminum metal layer made of the non-aluminum metal and a bonding alloy layer made of the aluminum bonding alloy. The non-aluminum metal layer and the bonding alloy layer are bonded together by pressure welding and diffusion bonding.