Set needle shield (1) intended to protect the needle (3) of a needle assembly, said shield assembly needle (1) comprising at least: - a support (2) intended to be fixed with respect to said needle (3), - a needle shield (8) intended to receive at least part of said needle (3), said needle shield (8) a longitudinal axis a and being axially movable with respect to said support (2 ) between at least one position in use, wherein said needle shield (8) is intended to leave a portion of said needle (3) uncovered, and a position of after use, wherein said needle guard ( 8) is intended to cover said needle (3), - thrust means (13) tending to displace said needle shield (8) from said in use position to said position after use, - a locking element ( 10) intended to prevent said needle guard (8) returns from its position after és use to its in-use position, said locking element (10) a longitudinal axis B and being movable radially with respect to said needle shield (8) between at least a free position, the longitudinal axis of said needle shield (8) and the longitudinal axis B of said locking element (10) coaxial with each other, and wherein said needle guard (8) to be moved from its in-use position to its position after use, and a position lock, while the longitudinal axis B of said locking element (10) radially spaced from the longitudinal axis a of said needle shield (8) and preventing movement of said needle shield (8) from its position after use into position in use, characterized in that said needle (3) not in contact with said locking element (10) at least when said needle shield (8) is moved from its in use position to its after use .Conjunto de protección de aguja (1) destinado a proteger la aguja (3) de un conjunto de aguja, comprendiendo dicho conjunto de protección de aguja (1) por lo menos: - un soporte (2) destinado a ser fijado con respecto a dicha aguja (3), - una protección de aguja (8) destinada a recibir por lo menos parte de dicha aguja (3), presentando dic
