A circuit board includes an aluminum nitride substrate, and a circuit pattern formed on the substrate and having a multilayered structure in which a metal oxynitride layer represented by formula Al.sub.u Ml.sub.v M2.sub.x O.sub.y N.sub.z (wherein M1 represents a metal selected from the group consisting of Ti, Cr, Ta, and Zr, M2 represents a metal selected from the group consisting of Ni, Pt, Pd, W, Nb, and Mo, u represents 3 to 50 atm %, v represents 3 to 78 atm %, x represents 0 to 50 atm %, y represents 0.005 to 25 atm %, and z represents 5 to 70 atm %), a bonding layer consisting essentially of a metal represented by M1, a barrier layer consisting essentially of a metal represented by M2, and a conductor layer consisting essentially of Au are stacked in the order named.