To easily remove an unnecessary part such as steps and a projecting part of a rut even if there are undulation and recessed and projecting parts in the unnecessary part to form a flat face in order to prevent the environment from being adversely affected economically.

Laser 11a is irradiated for a central point of a laser aiming guide 7 provided in a scraping blade mounting part 3 of a step removing device 1 from a semiconductor laser sighting device 11 in parallel with the longitudinal direction of a removing part 4. While keeping a condition in which laser 11a is always applied to the central point of the laser aiming guide 7, the step removing device 1 is moved to grind by a scraping blade 3a provided in the scraping blade mounting part 3.