In a non-invasive body component measuring apparatus for measuring a concentration of a body component in a measuring portion of a living body, and a method of non-invasively measuring the concentration of the body component, the non-invasive body component measuring apparatus includes a light source unit for generating light of a predetermined wavelength and for applying the light onto the measuring portion, a detection unit for detecting light reflected or transmitted by the measuring portion and for converting the detected light into an electrical signal, a signal processing unit for processing the electrical signal, and a body-apparatus interface unit for fixing a periphery of the measuring portion during measurement.