An automatic applicator for liquid pharmaceutical preparations, particularly for insulin, more particularly for multiple injection application of set doses of a medicine from an exchangeable container, comprising a body housing (1) connected to a housing (2) of an exchangeable container with a medicine, particularly insulin, having a plunger (12), suitable for expelling the medicine, the said plunger (12) being displaced only linearly by means of an integrated driving unit, suitable for immobilising, driving, leading linearly and blocking rotation of the said plunger (12), driven via a double action clutch, by a tensioning spring (15) situated in the body housing (1), the said spring (15) tensioned by a rotary hand-dose-setting ring (3) via the same double action clutch unit, wherein the said driving unit is activated by a trigger unit (13) and a dose is indicated by an indicating arrangement, according to the present invention is characterised in that it comprises at least one block key (5.6) placed in the upper part of the ratchet barrel (5), collaborating with at least one key (1.3) placed in the internal part of the cylindrical body housing (1).
