Needle protection device comprising: - a protective support delimiting a tube for receiving a syringe body; - a needle protector movable in relation to the protective support between a retracted position and a deployed position; - a compression spring applied between the protective support and the needle protector; said device being characterised by: - at least one pin of the needle protector and at least one corresponding groove of the protective support, receiving and guiding said pin, the at least one groove comprising: a first rectilinear part which extends substantially along an axis of the protective support over a length greater than the length of the needle to be protected; and a second rectilinear part that extends inclined in relation to said axis of the protective support, the first and second parts (38, 40) forming a V, one point of which is directed towards a proximal end of the device, said at least one pin and said at least one groove being configured for the initial retention of the needle protector against the action of the compressed spring in the retracted position, in which the at least one pin is retained in the second rectilinear part of the at least one corresponding groove, the needle protector being releasable by a displacement of the needle protector in relation to the protective support along a releasing direction, leading to the displacement of the at least one pin in said second rectilinear part up to the first rectilinear part of the at least one corresponding groove; and - at least one bracket integral with a first of the protector and of the support, the or each bracket being movable between a blocking position stopped against the second of the protector and of the support in the absence of a syringe in the protective support and an unblocking position separated from the second of the protector and of the support in the presence of a syringe in the protective support, the or each bracket having an actuating face that cooperates with the syringe body during its engagement in the tube of the support for the transitioning of the bracket from its blocking position to its unblocking position. - a protective support delimiting a tube for receiving a syringe body; - a needle protector movable in relation to the protective support between a retracted position and a deployed position; - a compression spring applied between the protective support and the needle protector; - at least one pin of the needle protector and at least one corresponding groove of the protective support, receiving and guiding said pin, - at least one bracket integral with a first of the protector and of the support, the or each bracket being movable between a blocking position stopped against the second of the protector and of the support in the absence of a syringe in the protective support and an unblocking position separated from the second of the protector and of the support in the presence of a syringe in the protective support, the or each bracket having an actuating face that cooperates with the syringe body during its engagement in the tube of the support for the transitioning of the bracket from its blocking position to its unblocking position.