A biological-information obtaining apparatus includes a light-emitting unit, an image sensor configured to capture images, in a time sequence, relating to a living body, and a lens. The apparatus also includes an extreme-occurrence-time obtaining unit configured to obtain times T1 and T2 at which extremes occur in time sequence with respect to brightness values of a first region and a second region, respectively, of each of the captured images. The apparatus further includes a pulse wave velocity (PWV) calculation unit configured to calculate a pulse wave velocity according to the equation, P=(Y×L/f)/(T2−T1), where Y represents a distance on the image sensor, the distance corresponding to a distance between the first region and the second region, f represents the focal length of the lens, and L represents a distance between the lens and the living body.
