A bioinert pipe includes a flow path inside, an inner wall of the flow path is composed of a resin tube and an outer peripheral surface of the resin tube is covered with a metal tube. The bioinert pipe includes an end portion extension member attached to an end portion of the metal tube, and the end portion extension member is made from a material harder than the resin tube and has a first surface and a second surface. The first surface is facing and in contact with an end surface of the metal tube and the second surface is directed opposite to the first surface. a through hole having an inner diameter substantially the same as an inner diameter of the metal tube is provided so as to pass from the first surface to the second surface in the end portion extension member. An edge of the through hole on the second surface of the end portion extension member has a chamfered shape, and the resin tube is inserted into the through hole. An end portion of the resin tube forms a flange portion by being by being bent outward in a radial direction of the flow path along the chamfered shape of the edge of the through hole.