PROBLEM TO BE SOLVED: To provide a medical fluid pressure detection device capable of detecting both negative and positive pressures of liquid, which can be prevented from being connected erroneously with respect to a flow channel of liquid.SOLUTION: A medical fluid pressure detection device 5 includes: a chamber unit 6 in which an introduction port 6aa for introducing liquid that circulates in a flow channel and a lead-out port 6ab for leading out the liquid are formed, and which can hold a predetermined volume of liquid； and a diaphragm 7 that defines the inside of the chamber unit 6 to a liquid chamber S1 where liquid is held, and a gas chamber S2 where predetermined gas is held, and can be deformed according to the pressure of the liquid in the liquid chamber S1. The medical fluid pressure detection device can detect the pressure of the liquid circulating in the flow channel based on a change in the pressure in the gas chamber S2 caused by the deformation of the diaphragm 7. The diaphragm 7 includes: a negative pressure detection region B that is deformed to one side when negative pressure is generated in the liquid in the liquid chamber S1； and a positive pressure detection region A that is deformed to the other side when positive pressure is generated in the liquid in the liquid chamber S1.SELECTED DRAWING: Figure 5【課題】液体の陰圧及び陽圧の何れも検出することができ、液体の流路に対して誤って接続してしまうのを防止することができる医療用液圧検出装置を提供する。【解決手段】流路にて流通する液体を導入する導入口６ａａ及びその液体を導出する導出口６ａｂが形成されるとともに、液体を所定容量収容し得るチャンバ部６と、チャンバ部６内を液体が収容される液室Ｓ１と所定の気体が収容される気室Ｓ２とに画成するとともに、液室Ｓ１内の液体の圧力に応じて変形し得るダイアフラム７とを具備し、ダイアフラム７の変形により生じた気室Ｓ２内の圧力変化に基づいて、流路を流通する液体の圧力を検出可能とされた医療用液圧検出装置５において、ダイアフラム７は、液室Ｓ１内の液体に陰圧が生じると一方に変形する陰圧検出用部位Ｂと、液室Ｓ１内の液体に陽圧が生じると他方に変形する陽圧検出用部位Ａとを有するものである。【選択図】図５
