The present invention concerns a seal device (24) for trocar, characterised in that it comprises, in the following order: - a proximal truncated conical element (42), of rigid elastic material, composed of one or more conical sectors (46), - a proximal membrane (49), of soft elastic material, centrally provided with a through hole (62), - a distal truncated conical element (44), of rigid elastic material, composed of one or more conical sectors (58), - a distal membrane with two or more truncated conical elements (55), of soft elastic material, overlapping each other, each one of which comprises a conical surface (52) and - a distal annular bracket (47), of rigid plastic material, the device (24) further comprising coupling mechanical means (43, 45, 48, 50, 51, 53, 54, 59, 60, 61) coupling the proximal truncated conical element (42), the proximal membrane (49), the distal truncated conical element (44), said two or more truncated conical elements (55) of said distal membrane and the distal annular bracket (47) to each other, whereby the proximal truncated conical element (42) is inserted in the distal truncated conical element (44) that is in turn inserted in said distal membrane. The present invention further concerns a trocar comprising such a seal device.La présente invention concerne un dispositif détanchéité (24) pour trocart, caractérisé en ce quil comprend, dans lordre suivant : - un élément conique tronqué proximal (42), de matériau élastique rigide, composé dun ou de plusieurs secteurs coniques (46), - une membrane proximale (49), de matériau élastique mou, pourvu, au centre, dun trou débouchant (62), - un élément conique tronqué distal (44), de matériau élastique rigide, composé dun ou de plusieurs secteurs coniques (58), - une membrane distale pourvue de deux, ou plus, éléments coniques tronqués (55), de matériau élastique mou, se chevauchant mutuellement, chacun deux comprenant une surface conique (52) et - un support annulaire distal (47), de matériau p
