To enhance a printing grade by uniformizing embossing depth or printing density by controlling the drive current ON-time of a printing head on the basis of ON-dot number data.

A printer driving circuit 15 controls the drive current ON-time of a printing head 2 corresponding to the ON-dot number data among 16 bit data transmitted serially. The drive current ON-time is controlled on the basis of the ON-dot number data. For example, drive current ON-times of two Stages are set to extend the drive current ON-time of ON-dot numbers 8-12 to ON-dot numbers 1-7 or to set the drive current ON-times of 12 stages individually corresponding to ON-dot numbers of 1-12 to control a drive current. The fluctuations of impact energy by ON-dot numbers are eliminated.