A manufacturing method includes a first repeating step of irradiating a base material with a pulse laser, having a spot diameter S, while relatively moving a laser head and the base material in a first direction, moving the laser head by a predetermined pitch width P in a second direction that intersects the first direction, and repeating irradiation by the pulse laser along the first direction and movement of the laser head in the second direction, and a second repeating step of irradiating the base material with the pulse laser while relatively moving the laser head and the base material in the second direction, moving the laser head by the pitch width in the first direction, and repeating irradiation by the pulse laser along the second direction and movement of the laser head in the first direction, wherein S