Abstract: Disclosed is an injection device including: —a needle support; —an injection needle integral with the needle support and having a free end arranged away from the needle support; and—a needle extraction mechanism including a base connected to the needle support and a plunger movable relative to the base between a needle use position and a needle extraction position. The base is movable relative to the needle support between an inactive position of the extraction mechanism and an active position of the extraction mechanism. The plunger includes an outer member and an inner member, movable relative to the outer member, from a retracted plunger configuration to a deployed plunger configuration wherein the plunger length is greater than in the retracted configuration.