PROBLEM TO BE SOLVED: To save labor of a position adjustment by a user in a noninvasive measurement of blood components.SOLUTION: A blood component measuring apparatus 10 acquires a blood vessel position viewed from a skin surface on the basis of a biological image, selects a measurement irradiation position (a measurement light-emitting element 53a) and a measurement light-receiving position (a measurement light-receiving element 59a) in such a manner as clamping a blood vessel site 6 appropriate for the measurement, and performs a measurement. Alternatively, a reference light-receiving position (a reference light-receiving element 59b) where no blood vessel is present towards the measurement irradiation position is selected, and absorption spectrum of the transmission light of the blood vessel is acquired by referring to the light-receiving result at the reference light receiving element 59b.【課題】非侵襲式の血液成分の測定において、使用者による位置調整の手間を省力化すること。【解決手段】血液成分測定装置１０によれば、生体画像をもとに皮膚面から見た血管位置を取得し、測定に適当な血管部位６を挟むように、測定用照射位置（測定用発光素子５３ａ）及び測定用受光位置（測定用受光素子５９ａ）を選択して測定を行う。また、測定用照射位置との間に血管が存在しないリファレンス用受光位置（リファレンス用受光素子５９ｂ）を選択し、このリファレンス用受光素子５９ｂでの受光結果を参照することで、血管の透過光についての吸収スペクトルを求める。【選択図】図１
