An apparatus for driving a printing head of a wire-dot printer, the head including a plurality of electroexpansive elements for driving respective printing wires cooperatively constituting a wire-dot matrix and in accordance with print pattern data designating the existence, or non-existence, of a dot to be printed by the respective, plural dot-impact printing wires in each of a succession of print cycles. Each electroexpansive element, selectively, is expanded and shrunk by an electrical charge/discharge, thereby to move the respective printing wire and perform a dot printing operation. The time intervals T1 and T2 respectively for the charge and discharge in each of a succession of printing cycles are: in the case of continuous dots, T1=A, T2 -B' for the first dot, T1=A', T2-B' for successive dots intermediate the first and the last dots, and T1=A', T2-B for the last dot of the continuous dots, and in the case of a single dot, T1=A, T2=B, wherein A>A', and B>B'.