The objective of the present invention is to provide a medical connecting fixture capable of allowing steam to circulate during steam sterilization, and capable of hermetically sealing an internal flow passage without the use of a separate clamping means.This medical connecting fixture is provided with: a main body portion 1 in which is formed an internal flow passage R capable of allowing a liquid flowing through one flow passage to flow to another flow passage； a proximal end portion (2a, 2b) which is formed in the main body portion 1 and which has a one-side connecting port (Ca1, Ca2) capable of connecting the internal flow passage R to said one flow passage； a distal end portion 3 which is formed in the main body portion 1 and which has an other-side connecting port Cb capable of connecting the internal flow passage R to the other flow passage； a one-side lid portion (5a, 5b) capable of closing the one-side connecting port (Ca1, Ca2)； and an other-side lid portion 6 capable of switching between a closed state in which the other-side connecting port Cb is closed and the internal flow passage R is in a hermetically sealed state, and a ventilated state in which ventilation is possible while the other-side connecting port Cb is covered.L'objectif de la présente invention est de fournir un dispositif de raccordement médical pouvant permettre à la vapeur de circuler pendant la stérilisation à la vapeur, et capable de sceller hermétiquement un passage d'écoulement interne sans utiliser de moyen de serrage séparé. Ce dispositif de raccordement médical est pourvu : d'une partie corps principal 1 dans laquelle est formé un passage d'écoulement interne R apte à permettre à un liquide s'écoulant à travers un passage d'écoulement de s'écouler vers un autre passage d'écoulement； d'une partie d'extrémité proximale (2a, 2b) qui est formée dans la partie corps principal 1 et qui a un orifice de raccordement d'un côté (Ca1, Ca2) apte à raccorder le passage d'écoulement interne
