There is provided a novel Cu bonding wire that achieves a favorable FAB shape and achieve a favorable bond reliability of the 2nd bonding part even in a rigorous high-temperature environment. The bonding wire for semiconductor devices includes a core material of Cu or Cu alloy, and a coating layer having a total concentration of Pd and Ni of 90 atomic% or more formed on a surface of the core material. The bonding wire is characterized in that:

in a concentration profile in a depth direction of the wire obtained by performing measurement using Auger electron spectroscopy (AES) so that the number of measurement points in the depth direction is 50 or more for the coating layer,
a thickness of the coating layer is 10 nm or more and 130 nm or less,
an average value X is 0.2 or more and 35.0 or less where X is defined as an average value of a ratio of a Pd concentration CPd (atomic%) to an Ni concentration CNi (atomic%), CPd/CNi, for all measurement points in the coating layer,
the total number of measurement points in the coating layer whose absolute deviation from the average value X is 0.3X or less is 50% or more relative to the total number of measurement points in the coating layer, and
the bonding wire satisfies at least one of following conditions (i) and (ii):

(i) a concentration of In relative to the entire wire is 1 ppm by mass or more and 100 ppm by mass or less; and
(ii) a concentration of Ag relative to the entire wire is 1 ppm by mass or more and 500 ppm by mass or less.