[Object] To provide a bonded body of an aluminum alloy and a copper alloy and a bonding method for the bonded body, the bonded body being bonded by a novel bonding method which ensures excellent bonding properties, small material deformation during bonding, and high reliability. [Solving Means] A bonded body made of an aluminum alloy and a copper alloy and obtained by employing the aluminum alloy as one member to be bonded and the copper alloy as the other member to be bonded, the one bonded member and the other bonded member being bonded to each other through metallic connection, wherein the one bonded member is made of comprising an aluminum alloy containing Cu: 3.0 mass % to 8.0 mass % and Si: 0.1 mass % to 10 mass % with balance being Al and unavoidable inevitable impurities, and satisfying the chemical formula: C + 2.4 · S · 7.8 where C (mass %) is a Cu concentration and S (mass %) is a Si composition concentration is satisfied, and the other bonded member is made of comprising a copper alloy having a higher solidus temperature than the one bonded member. A bonding method for the bonded body is also provided.