PURPOSE: To arrange so that printing may be carried out at selected character pitch by setting values determined by a relationship between the dot pitch of characters to be printed and a pitch between printing element rows of a printing head and the travelling speed of a printing head.

CONSTITUTION: A printing head 1 consists of dot pin Wa1... of a front row and dot pin Wb1... of a back row arranged in two zigzag rows. When dot characters are printed, the dot pin Wa of a front row which has arrived at a printing position F is caused to protrude and print at timing signal a, and after a delay time T from the signal a to the setting of a timer, that is, after the dot pin Wb of a back row of the printing head 1 which travels at space speed V arrives at a printing position G, the dot pin Wb is caused to protrude and print. Consequently, at the position G, dots printed by the dot pin Wa of a front row before "n" frequency and dots by the dot pin Wb of a back row are synthesized to form dots. Thus it is possible to change a character pitch selectively and print in characters suitable to the form of recording paper.