An apparatus and a method for treating a surface to definitely, and with a high quality, finish an object to be processed, are obtained. In the step of a first check, the numbers of objects (W) that are carried into areas (20A, 42A, 74A) where the steps of pre-cleaning, shot peening, and post-cleaning, are carried out, are counted and the conditions of the surfaces of the objects are detected. In the step of a second check, the numbers of objects (W) that are carried out of the areas are counted and the conditions of the surfaces of the objects are detected.