Device (100) for injection of fluid product having a syringe body (101) and a needle (110) fixed in an axial end projection (102) of the syringe body said end projection (102) having an axial end surface (103) said injection device having a needle protection device (200) said protection device being fixed on said injection device in a storage position said protection device being removable from said injection device said protection device having an internal body (210) made of substantially flexible and/or deformable material and an external body (220) made of substantially rigid material said internal body (210) in the storage position closing the dispensing orifice (111) of said needle (110) in a leaktight manner and cooperating with said injection device (100) in a leaktight manner and said external body (220) having a fastening part (228) which in the storage position cooperates with a shoulder (104) of said injection device (100) in order to fix said protection device (200) on said injection device (100) said internal body (210) having a proximal axial end edge (213) which in the storage position is designed to cooperate in a leaktight manner with the syringe body (101) exclusively via said axial end surface (103) said internal body (210) being made of a material with the following properties: a hardness greater than 55 Shore A in particular greater than 60 Shore A an elasticity greater than 8 MPa in particular greater than 10 MPa a compression set of less than 30% in particular less than 25% a density greater than 1 in particular greater than 1.3.
