A wire material has a prescribed chemical composition in which a solid solution N is no more than 0.0015%, the structure within a cross section of a region extending from the surface of the wire material to a depth equal to one-fourth the diameter of the wire material includes 90.0 area% or more of pearlite and a total of 0-10.0 area% of bainite and ferrite, the total value of martensite and cementite content of the region extending from the surface of the wire material to a depth equal to one-fourth the diameter of the wire material is limited to no more than 2.0 area%, and the calculated maximum TiN-based inclusion size of the surface layer portion of the wire material is 50 micrometers or less.