A semiconductor element bonding structure capable of strongly bonding a semiconductor element and an object to be bonded and relaxing thermal stress caused by a difference in thermal expansion, by interposing metal particles and Ni between the semiconductor element and the object to be bonded, the metal particles having a lower hardness than Ni and having a micro-sized particle diameter. A plurality of metal particles 5 (aluminum (Al), for example) having a lower hardness than nickel (Ni) and having a micro-sized particle diameter are interposed between a semiconductor chip 3 and a substrate 2 to be bonded to the semiconductor chip 3, and the metal particles 5 are fixedly bonded by the nickel (Ni). Optionally, aluminum (Al) or an aluminum alloy (Al alloy) is used as the metal particles 5, and aluminum (Al) or an aluminum alloy (Al alloy) is used on the surface of the semiconductor chip 3 and/or the surface of the substrate 2.