PURPOSE: To conduct alignment while using positioning marks as references, and to perform accurate alignment comparatively simply by giving the positioning marks in response to thermal recording elements in specified order of each thermal head.

CONSTITUTION: A first positioning mark 106 and second positioning marks 107 are formed onto an alumina substrate 101. The first positioning mark 106 is formed at a position corresponding to the specific thermal recording element of the thermal recording element row of a thermal head 10. An apex A is given as a triangular mark corresponding to a No. 3 thermal recording element from the left. Since the intervals of the array of the thermal recording elements are extremely reduced generally in such a thermal head, the size of the positioning mark 106 corresponds to the width of several dozen thermal recording elements in the actual thermal head 10.