A device for automatic injection of a product into an injection site, said device being in one of a passive and active state, triggering of injection being prevented when said device is in its passive state and permitted when said device is in its active state, said device having: - a housing (30, 30a, 30b) receiving a container, the container being provided at its distal end with a needle, the container being movable relative to the housing upon activation of triggering means between an initial position, in which the tip of the needle does not extend beyond the distal end of the housing, and an insertion position, in which the tip of the needle extends beyond the distal end of the housing, distally spaced from the initial position, the container being in one of a passive state and an active state, movement of the container out of its initial position being prevented when the container is in its passive state, and being permitted when the container is in its active state, and - a safety shield coupled with the housing and being movable with respect to the housing along a movement path having a predetermined length, the safety shield being movable between a first position and a second position a first distance that is less than the predetermined length, and between the second position and a third position a second distance that is less than the predetermined length, - first retaining means (60, 61, 54a) for maintaining the container in its passive state, - second retaining means (34a, 81b) for maintaining said device in its passive state, said device being characterized in that it further comprises: - first deactivating means (50, 53) movable coincident with movement of the safety shield the first distance to cooperate with first retaining means (61, 54a) so as to place the container in the active state, and - second deactivating means (50, 50a) movable coincident with movement of the safety shield the second distance to cooperate with second retaining means (34a, 81b) so as to place the device in its active state, wherein part of the first and second deactivating means are formed on a sleeve coupled to the safety shield and being received within said housing, the sleeve being movable in rotation and in translation with respect to the housing when the safety shield moves from its first position to its second position, the sleeve being movable in translation with respect to the housing when the safety shield moves from its second position to its third position. - a housing (30, 30a, 30b) receiving a container, the container being provided at its distal end with a needle, the container being movable relative to the housing upon activation of triggering means between an initial position, in which the tip of the needle does not extend beyond the distal end of the housing, and an insertion position, in which the tip of the needle extends beyond the distal end of the housing, distally spaced from the initial position, the container being in one of a passive state and an active state, movement of the container out of its initial position being prevented when the container is in its passive state, and being permitted when the container is in its active state, and - a safety shield coupled with the housing and being movable with respect to the housing along a movement path having a predetermined length, the safety shield being movable between a first position and a second position a first distance that is less than the predetermined length, and between the second position and a third position a second distance that is less than the predetermined length, - first retaining means (60, 61, 54a) for maintaining the container in its passive state, - second retaining means (34a, 81b) for maintaining said device in its passive state, - first deactivating means (50, 53) movable coincident with movement of the safety shield the first distance to cooperate with first retaining means (61, 54a) so as to place the container in the active state, and - second deactivating means (50, 50a) movable coincident with movement of the safety shield the second distance to cooperate with second retaining means (34a, 81b) so as to place the device in its active state,