An apparatus for estimating bio-information may include an optical sensor comprising a light emitter disposed on a substrate, and a plurality of light receiving groups which are arranged on a plurality of concentric circles on the substrate, at different distances from the light emitter, respectively, and a processor configured to drive one of the plurality of light receiving groups that is selected based on a type of the bio-information to be estimated, and estimate the bio-information of an object based on optical signals detected by the driven light receiving group