According to one embodiment, there is provided an active material including a titanium oxide compound having a monoclinic titanium dioxide crystal structure and satisfying the equation (I). S1/(S2+S3)≦1.9  (I). In the above equation, S1 is the peak area of a peak existing in a wavelength range from 1430 cm−1 to 1460 cm−1, S2 is the peak area of a peak existing in a wavelength range from 1470 cm−1 to 1500 cm−1, and S3 is the peak area of a peak existing in a wavelength range from 1520 cm−1 to 1560 cm−1, in the infrared diffusion reflective spectrum of the active material after pyridine is absorbed and then released.