According to one embodiment, an active material is provided. This active material includes active material particles each allowing lithium to be inserted thereinto and extracted therefrom in the range of 0.5 V to 2V (vs. Li+/Li), and carbon material layers at least partially coating the active material particles. The active material has a BET specific surface area S of 2 m2/g to 20 m2/g in accordance with a nitrogen adsorption method. Between the BET specific surface area S and the proportion M (mass %) of the mass of the carbon material layers to the total mass of the active material particles and carbon material layers, the ratio of S/M (m2/g) meets 0.5≤S/M≤5.