PROBLEM TO BE SOLVED: To provide a pressure measurement instrument capable of miniaturizing a housing.SOLUTION: A pressure measurement instrument 1 measures the pressure of blood flowing in a blood circuit 3 and includes a housing 11 and a barrier membrane 13. The housing 11 has an internal space 11f and the internal space 11f is divided into a blood chamber 21 and a gas chamber 22 via the barrier membrane 13. The barrier membrane 13 changes the position in accordance with the internal pressure of the blood chamber 21. Besides, the barrier membrane 13 has an uneven shape so as to form the first convex space 14 projecting toward the gas chamber 22 and forming a part of the blood chamber 21 and the second convex space 15 projecting toward the blood chamber 21 and forming a part of the gas chamber 22. The volumetric capacity of the first convex space 14 is larger than the volumetric capacity of the second convex space 15.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2016,JPO&INPIT
