An automatic applicator for liquid pharmaceutical preparations, particularly for multiple injection application of set doses of a medicine from an exchangeable container is provided. The automatic applicator includes a body housing connected to a housing of an exchangeable container with a medicine having a plunger, the said plunger being displaced only linearly by an integrated driving unit, suitable for immobilizing, driving, leading linearly and blocking rotation of the plunger, driven via a double action clutch, by a tensioning spring situated in the body housing, the spring tensioned by a rotary hand-dose-setting ring via the double action clutch, wherein the driving unit is activated by a trigger unit and a dose is indicated by an indicating arrangement. The automatic applicator further includes at least one block key placed in an upper part of a ratchet barrel, collaborating with at least one key placed in an internal part of the body housing.