NOVELTY - An active substance comprises particles of niobium titanium composite oxide and a phase comprising a carbon material, where the phase is formed on a part of the surface of the particles, the carbon material shows G band observed at 1530-1630 cm-1 and a D band observed at 1280-1380 cm-1, and a ratio (IG/ID) between a peak intensity (IG) of the G band and a peak intensity (ID) of the D band to be 0.8-1.2, in a Raman chart obtained by Raman spectrometry using a 532-nm measuring light source.    USE - Active substance for use in nonaqueous electrolyte battery (claimed) such as lithium-ion secondary battery that is utilized as power source for vehicles such as hybrid vehicles or electric cars or a large-sized power source for electricity storage.    ADVANTAGE - The active substance has improved crystal stability, ensured reduction stability of niobium element, reduced internal resistance, improved current collection performance, and provides the battery with high energy density, rapid charge and discharge performances and long-term reliability.    DETAILED DESCRIPTION - An active substance comprises particles of niobium titanium composite oxide (Ti (1-x)M1xNb(2--y)M2yO7), and a phase comprising a carbon material, where x is more than 0, but less than 1, M1 and M2 is selected from niobium, vanadium, tantalum, iron, titanium, bismuth, antimony, arsenic, phosphorus, chromium, molybdenum, tungsten, boron, sodium, magnesium, aluminum and silicon, and the M1 and M2 are identical or different from each other, the phase is formed on a part of the surface of the particles, the carbon material shows G band observed at 1530-1630 cm-1 and a D band observed at 1280-1380 cm-1, and a ratio (IG/ID) between a peak intensity (IG) of the G band and a peak intensity (ID) of the D band to be 0.8-1.2, in a Raman chart obtained by Raman spectrometry using a 532-nm measuring light source. INDEPENDENT CLAIMS are also included for the following:    (1) a nonaqueous electrolyte battery    (2) a battery pack    (3) a method for manufacturing an active substance.