Blood component measuring apparatus (10A), at least capable of emitting illumination light source (12), a light receiving portion having a capable of receiving sensitivity capable of emitting light (12) illumination source (14) light in the near infrared region, I and a (20) calculating means for calculating a holding mechanism for holding and fixing (11) and body part (16), the concentration of blood components in the body part (11). Calculation means (20), one body part (11), the transmitted light intensity of the wavelength of the second transmitted light intensity S1 of the first wavelength that is easily absorbed relative to hemoglobin, less likely to be absorbed by the hemoglobin relative for the portion of the minimum ratio of S2 (S1 / S2) to calculate the concentration of blood components.血液成分測定装置(10A)は、少なくとも近赤外域の光を出射可能な照射光源(12)と、照射光源(12)で出射可能な光を受光可能な感度を持つ受光部(14)と、生体部位(11)を保持・固定する保持機構(16)と、生体部位(11)における血液成分の濃度を算出する演算手段(20)とを備える。演算手段(20)は、生体部位(11)のうち、血色素に相対的に吸収されやすい第1の波長の透過光強度S1と、血色素に相対的に吸収されにくい第2の波長の透過光強度S2との比(S1/S2)が最小の箇所について、血液成分の濃度を算出する。
