In manufacturing method for a thermal head, concave portions, including a reference concave portion, are formed on a surface of a substrate so that a length of each of the concave portions other than the reference concave portion increases as a distance from the reference concave portion in a length direction increases and so that a width of each of the concave portions other than the reference concave portion increases as a distance from the reference concave portion in a width direction increases. A mark identifying the reference concave portion is formed on the surface of the substrate. An insulating film is thermally fusion bonded to the surface of the substrate including the concave portions formed thereon. Heating resistors are formed on the insulating film using a photo mask by aligning the photo mask with the substrate in accordance with the reference concave portion to form the heating resistors so as to be opposed to the plurality of concave portions.