A thermal printhead (A) includes an insulating substrate (1), a heating resistor (2) provided on the substrate (1) and a protective film (4) covering the heating resistor (2). The protective film (4) is made up of a first layer (41), a second layer (42) and a third layer (43). The first layer (41) is held in contact with the heating resistor (2). The second layer (42) covers the first layer (41). The second layer (42) is harder than the first layer (41) and has a higher thermal conductivity than that of the first layer (41). The third layer (43) is the outermost layer and covers the second layer (42). The third layer (43) is harder than the second layer (42) and thinner than the second layer (42).