A diagnosis method and apparatus for measuring blood hemoglobin concentration, oxygen saturation, pulse rate, respiration rate, or degree of aging of blood vessels using light includes an input/output unit for receiving a command for measurement from a user and for providing information on the result of a measurement to the user; a control unit for receiving the command for measurement from the input/output unit and for generating a control signal; a light generating unit for generating at least two light beams for measurement according to the control signal; a light receiving unit for receiving the light beams transmitted through an object that is subject to measurement and for converting the received light beams into electrical signals; and a data processing unit for processing the electrical signals received from the light receiving unit and for outputting information on the result of a predetermined measurement.