The application relates to a blood collection device comprising: a cannula hub (10) defining a chamber (28)； a cannula (56) defining an axis and having a distal end, a proximal ed and a lumenextending therethrough, the cannula being mounted to the cannula hub such that the distal end and the proximal end of the cannula are external of the cannula hub and such that thelumen trough the cannula communicates with the chamber by means of an opening (58)； a closed sleeve (34) mounted over a portion (32) of the cannula disposed externally of the cannula hub； and a venting mechanism (38) providing communication between the chamber and ambient surroundings, the venting mechanism (38) comprising a tubular insert (40) defining a fluid passage (42) therethrough and a membrane (44) extending across the fluid passage (42), wherein the membrane (44) is made from a material permeable for air and substantially impermeable for blood, the tubular insert (40) of the venting mechanism (38) having an outer collar (52) formed at its outer surface, whereby the tubular insert (40) of the venting mechanism (38) is received in a tubular projection (50) extending from the cannula hub； and the outer collar is formed adjacent an end facing away from the cannula hub, wherein an outer diameter of the outer collar is substantially equal to an outer diameter of the tubular projection.
