A dermatological liquid injection apparatus (1) comprising: a body unit (10) comprising a drive device (11), a cam element (13) rotated by the drive device, and a drive element connection (15) actuated alternatively by the cam element； a needle unit (50) removably mounted on a leading end of the body unit (10) and comprising a plurality of needles (53d)； a rubber element (56) installed in the needle unit, to prevent blood and the mixture of liquids that are discharged from a patient's skin and circulating in the needle unit (50), from flowing to the body unit (10) during a medical intervention； characterized in that a rotation element (19) is coupled to the body unit (10) so that it rotates； and a mobile element (30) is threaded on the rotation element (19) on one side and detachably coupled on one side of a cap unit (54) on the other side, in which the mobile element (30) zooms in or out the plurality of needles (53d) of an edge unit (54c) based on the edge unit that is a leading end of the cap unit (54) by moving the cap unit forward and backward when the rotating element (19) rotates in one direction and one opposite direction, and defines the depth of insertion of the plurality of needles (53d) in the skin, and in which the cap unit (54) surrounds a needle holder (53) and a liquid reservoir (52) and comprises a support unit (54f) in which a mobile rod (51) penetrates, wherein said needle holder (53) comprises the plurality of needles (53d) and a plurality of liquid discharge holes (53e) for the expulsion of liquid, and in which the needle unit (50) includes and the mobile rod (51), the liquid reservoir (52), the needle holder (53), the cap unit (54), the rubber element (56) and a coil spring (55).Un aparato de inyección de líquido dermatológico (1) que comprende: una unidad de cuerpo (10) que comprende un dispositivo de accionamiento (11), un elemento de leva (13) puesto en rotación por el dispositivo de accionamiento, y un elemento de conexión (15) accionado de
