Yarn is dispensed by a yarn guide mobile in translation parallel to generatrices of a rotary holder. The device comprises a carriage receiving the yarn guide and having fittings for being coupled with a flexible transmission and driving member adapted to impart to the yarn guide a reciprocating movement, in combination with a translational guide, parallel to the generatrices of the rotary holder. The yarn guide, the translational guide and the fittings being offset at an angle on the carriage to generate an additional speed component proximate to changeover points.