The present invention relates to a medical liquid pressure detection device whereby both negative pressure and positive pressure of a liquid can be detected and erroneous connection to a flow path of the liquid can be prevented. A medical liquid pressure detection device (5) provided with: a chamber part (6) capable of accommodating a predetermined volume of a liquid, an inlet port (6aa) for introducing liquid flowing through a flow channel, and an outlet port (6ab) for discharging the liquid being formed in the chamber part (6)； and a diaphragm for partitioning the inside of the chamber part (6) into a gas chamber (S1) in which the liquid is accommodated and an air chamber (S2) in which a predetermined gas is accommodated, the diaphragm (7) being capable of deforming in accordance with the pressure of the liquid in the liquid chamber (S1)； the medical liquid pressure detection device (5) being capable of detecting the pressure of the liquid flowing through the flow channel on the basis of a pressure change in the gas chamber (S2) resulting from deformation of the diaphragm (7)； wherein the diaphragm (7) having a negative pressure detecting portion (B) for deforming in one direction when a negative pressure occurs in the liquid in the liquid chamber (S1), and a positive pressure detecting portion (A) for deforming in the other direction when a positive pressure occurs in the liquid in the liquid chamber (S1).La présente invention concerne un dispositif de détection de pression de liquide médical, moyennant quoi une pression négative et une pression positive d'un liquide peuvent toutes deux être détectées et une mauvaise liaison à un trajet d'écoulement du liquide peut être empêchée. Un dispositif de détection de pression (5) de liquide médical comporte : une partie chambre (6) pouvant recevoir un volume prédéfini d'un liquide, un orifice d'entrée (6aa) destiné à introduire un liquide s'écoulant à travers un canal d'écoulement et un orifice de sortie (6ab) destiné à
