Problem to be solved: to provide a technique for suppressing the lowering of the measurement accuracy of the amount of components in the liquid flowing out from the outlet.The main liquid containing the subject to be measured is collected.A liquid collector 21 for draining the mixed liquid formed by mixing the primary liquid with the auxiliary liquid supplied from the outsideA first passage located downstream of the liquid collecting partA first sensing part 22 having a concentration measuring part in a mixed liquid for measuring a concentration of a first measurement object which is a concentration of the object to be measured in the mixed liquid at a first flow path and positioned in the first passageAn apparatus for measuring a component concentration.Diagram【課題】流出元から流出する液体中の成分の量の測定精度の低下を抑制する技術を提供する。【解決手段】測定対象である測定対象成分を含んだ主液体を収集するとともに、主液体と外部から供給される補助液体とを混合させることによって成る混合液体を流出させるための液体収集部２１と、液体収集部２１の下流に位置する第１流路と、前記第１流路に位置して前記混合液体中の前記測定対象成分の濃度である第１測定対象成分濃度を測定する混合液体中濃度測定部とを備える第１センシング部２２と、を備える成分濃度測定装置。【選択図】図１
