PROBLEM TO BE SOLVED: To provide a measuring chamber of an extracorporeal circulation device for reducing the risk of liquid leakage and improving manufacturing efficiency. SOLUTION: The measuring chamber 51 stores reservoirs 230, 231, 232 for storing a liquid, and internal flow paths 240, 241, which communicate from the upper part of the reservoir through the internal space R of the reservoir to the lower part of the internal space. 242, and the reservoirs and the corresponding internal channels are integrally formed. [Selection diagram] Fig. 5【課題】液漏れのリスクを低減し、製造効率の向上を図る体外循環装置の計量チャンバーを提供する。【解決手段】計量チャンバー５１は、液体を貯留する貯留部２３０、２３１、２３２と、貯留部の上部から貯留部の内部空間Ｒを通って内部空間の下部に連通する内部流路２４０、２４１、２４２と、を備え、各貯留部と、それに対応する内部流路は、一体成形されている。【選択図】図５
