Automatic fluid product injection device comprising a body (1) attached to a holder (2) intended to contact a region to be injected, said body (1) containing one or more fluid product reservoirs (5), each containing an injection plunger (6), a needle assembly (4) having an injection needle (40) for penetrating into the region to be injected, and an injection mechanism (7, 8, 9, 10, 11), said needle assembly (4) comprising an injection needle for penetrating into the region to be injected and a shape memory alloy insertion actuator, wherein the injection mechanism comprises a retraction ring (42), a needle holder (44), an insertion ring (45), a retraction spring (46), an actuating ring (47) and an insertion spring (48), the insertion spring (48) and the retraction spring (46) being, at rest, kept in a compressed state by respective locking means, and wherein the actuation of the actuator (49) via heating, such that it reaches about 50% of the possible contraction, causes the actuating ring (47) to move relative to the insertion ring (45) to which one end of the actuator (49) is attached, said movement causing the release of the needle holder (44), thereby extending the insertion spring (48), which causes the needle holder (44) and the injection needle (40) to penetrate into the region to be injected, and the actuation of the actuator (49) via heating, such that it reaches 100% of the possible contraction, causes the actuating ring (47) to move relative to the retraction ring (42), said movement causing the release of the insertion ring (45) and of the assembly composed of the needle holder (44) and the injection needle (40), such that the retraction spring (46) retracts the injection needle (40) out of the region to be injected.Dispositif d'injection automatique de produit fluide comportant un corps (1) fixé à un support (2) destiné à venir au contact d'une zone à injecter, ledit corps (1) contenant un ou plusieurs réservoirs (5) de produit fluide contenant chacun un
