PURPOSE: To provide a thermal head capable of forming a sharp printing image having no density irregularity.
CONSTITUTION: In a thermal head wherein a head substrate 1 having a plurality of heating resistors 4 linearly arranged to the surface thereof is mounted on a support plate 2, a high heat conductivity member 7 having heat conductivity higher than that of the head substrate 1 and a low heat conductivity member 8 having heat conductivity lower than that of the support plate 2 are interposed between the head substrate 1 and the support plate 2 so that the high heat conductivity member 7 is positioned on the side of the head substrate 1. The heat generated by the heating resistors 4 is diffused by the high heat conductivity member 7 and the temp. of the region where at least a heating resistor 3 is formed of the head substrate 1 becomes uniform. Therefore, the printing image formed on the thermal paper also becomes uniform in density to be enhanced in quality.