An apparatus for insertion of a medicine peg (3) into the skin (4) has a barrel (2) wherein the medicine peg (2) is stored and in which a plunger (8) behind said peg (2) can be moved to press the peg out through an end of the barrel (2) pressed against the skin (4) where it is intended to insert the peg (3), The plunger (8) is a part of a flexible rod construction (6, 7, 8) which can be passed from a first non rectilinear constellation, by which the plunger (8) is withdrawn in the barrel (2) to a position leaving space for the medicine peg (3) in front of the plunger (8), to a rectilinear constellation by which the plunger (8) projects from the end of the barrel (2) and further to a new non rectilinear position in which the end of the plunger (8) is withdrawn in the barrel (2).