A device (1) for the direct detection of the endovascular pressure of a fluid in a vessel allows increasing the measuring accuracy, both related to static and dynamic quantities, detected through an air column which inside capillary ducts, is in contact with the endovascular fluid which exerts its pressure thereon, by separating at the same time such air column from outside in each process phase, and then by preventing that the fluid, the pressure thereof has to be measured, is polluted or infected thereby, and comprising, to this purpose, a connector (5) with a valve (13, 14), which defines a connection terminal cavity (63) which is arranged outside a needle-holding element (11) and is in fluid communication with said one or more capillary ducts (16) through a duct (6) extending from said needle-holding element (11) to said connector (5) and a re-usable element (2) including at least a pressure sensor (25) and comprising means for connecting to said connector (5) at said terminal cavity (63) of the disposable portion (3), apt to put into communication an inner space (50) of said re-usable element (2), which receives said at least a pressure sensor (25), with said terminal cavity (63), the opening of said valve (13, 14) being determined by the connection between the re-usable element (2) and said disposable portion (3).La présente invention concerne un dispositif (1) pour la détection de la pression endovasculaire dun fluide dans un vaisseau qui permet laugmentation de la précision de mesure, à la fois liée à des quantités statiques et dynamiques, détectée par lintermédiaire dune colonne dair qui, à lintérieur de conduits capillaires, est en contact avec le fluide endovasculaire qui exerce sa pression sur celle-ci, en séparant simultanément une telle colonne dair de lextérieur dans chaque phase de processus, et ensuite en empêchant que le fluide, dont la pression doit être mesurée, soit pollué ou infecté par celle-ci, et comprenant, à cet effet, un connecteur (5) av