The present invention relates to an adjustment system for adjusting the base of the print head of a plotter with respect to the printing base of the plotter, said base of the head comprising a substantially vertical fixed part (1) and a substantially horizontal adjustable part (2), and it is characterized in that said adjustment means comprise a substantially vertical rotating shaft (4) located between said adjustable part (2) and said fixed part (1); at least one substantially horizontal adjustment element (3) regulating the angular position of said adjustable part (2) with respect to said fixed part (1); and a plurality of substantially vertical adjustment elements (3) regulating the inclination and height of said adjustable part (2) with respect to said fixed part (1). It enables the base of the print head to be regulated easily and precisely, without any play.