An apparatus for obtaining oxygen-saturation information including a light-emitting unit configured to emit light, an image-capturing unit configured to capture images, in time sequence, obtained by irradiating a living body with the light emitted and by causing the light to be transmitted through or reflected by the living body, the image-capturing unit being sensitive to at least two color components, an extreme generation unit configure to generate, for each of the captured images in the time sequence, a maximum value and a minimum value of each of the color components in a certain area of the captured image, and an oxygen-saturation calculation unit configured to calculate oxygen saturation on the basis of the maximum value and the minimum value of each of the color components in the certain area of the captured image.
