The present invention relates to a needle assembly (1) comprising:a needle hub (4) having a needle (5) with a distal tip (6),a ring (42) for protecting the needle in one of a storage condition or end-of-use condition of the needle assembly,- foldable means (40) for moving the protective ring,- biasing means (30) for urging the foldable means from their folded configuration to their unfolded configuration,- retaining means for maintaining the biasing means in an intermediate stressed state at least in the storage condition of the needle assembly,- deactivating means (47a) for releasing said retaining means at least at the end of the injection step. The invention also relates to an injection device (3) comprising such a needle assembly and a container (2).
