An apparatus for obtaining bio information includes: a first electrode portion including a current electrode and a voltage electrode arranged to contact a first body portion of a subject; a second electrode portion including a current electrode and a voltage electrode arranged to contact a second body portion of the subject; and a measuring unit configured to measure a bio impedance of the subject by applying a current to the current electrodes of the first and second electrode portions and detecting a voltage at the voltage electrodes of the first and second electrode portions. In order to decrease errors of a measured bio impedance, contact resistances of the first and second body portions of the subject contacting the current electrode and the first and second body portions of the subject contacting the voltage electrode are different from each other, for at least one of the first and second electrode portions.