Battery active material, nonaqueous electrolyte battery and battery pack

According to one embodiment, a battery active material is provided. The battery active material includes monoclinic complex oxide represented by the formula LiTiM1NbM2O(0 ≤ x ≤ 5, 0 ≤ y ≤ 1, 0 ≤ z ≤ 2, -0.3 ≤ δ ≤ 0.3). In the above formula, M1 is at least one element selected from the group consisting of Zr, Si and Sn, and M2 is at least one element selected from the group consisting of V, Ta and Bi.