An organism information measuring device has two light irradiating parts that irradiate light of short and long wavelength, respectively, toward an organism, and two light receiving parts that receive backward scattered light from the organism and produce organism information signals according to the quantity of received light. A data processor determines organism information indicative of a condition of the organism based on the organism information signals. The two light irradiating parts may be combined into a single light irradiating part, with one of the light receiving parts disposed farther from the light irradiating part than the other and having a light receiving area larger in size than that of the other and proportional to the distance thereof from the light irradiating part.