We consider the unit tangent sphere bundle of Riemannian manifold ( M, g ) with g-natural metric
G̃ and we equip it to an almost contact B-metric structure. Considering this structure, we show that there is
a direct correlation between the Riemannian curvature tensor of ( M, g ) and local symmetry property of G̃.
More precisely, we prove that the flatness of metric g is necessary and sufficient for the g-natural metric G̃ to
be locally symmetric.