There is provided a Cu bonding wire having a Pd coating layer on a surface thereof, that improves bonding reliability of a ball bonded part in a high-temperature and high-humidity environment and is suitable for on-vehicle devices.The bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer formed on a surface of the Cu alloy core material, and the bonding wire contains In of 0.011 to 1.2% by mass and has the Pd coating layer of a thickness of 0.015 to 0.150 μm. With this configuration, it is able to increase the bonding longevity of a ball bonded part in a high-temperature and high-humidity environment, and thus to improve the bonding reliability. When the Cu alloy core material contains one or more elements of Pt, Pd, Rh and Ni in an amount, for each element, of 0.05 to 1.2% by mass, it is able to increase the reliability of a ball bonded part in a high-temperature environment of 175° C. or more. When an Au skin layer is further formed on a surface of the Pd coating layer, wedge bondability improves.