To provide a wire for reinforcing a rubber article, on being especially applied to a tire, capable of making the tire further have a light weight, without causing faults such as wire crease, etc., and also without damaging various performances of the tire such as driving stability, etc., and the rubber article by using the same.

This reinforcing wire 1 for the rubber article has a track-shaped flat cross section consisting of a pair of parallel linear parts 11, and a pair of opposing circular arc parts 12 projecting to outside, where the thickness of the wire is T (mm), and the radius of curvature of the circle is R (mm), the relationship expressed by the following formulae (1) and (2) are satisfied, and the wire is imparted with a wave patterning at least in one direction of the wire thickness direction or the width direction. 0.15T0.30 (1), 0.6354TR0.77T+0.019 (2).