A thermal printhead (A1) includes an insulating substrate and a heating resistor element (3) formed on the substrate and elongated in the primary scanning direction. A plurality of electrodes are connected to the heating resistor element (3). The electrodes and the heating resistor element (3) are covered by a protective film (4). The protective film (4) includes a first layer (41), a second layer (42) and a third layer (43). The second layer (42) is porous and includes a plurality of pores (42a). The third layer (43) partially enters each of the pores (42a) so that the upper surface pf the protective film (4) is an irregular surface including a plurality or recesses (4a).