Particularly, a thin-film solar cell panel or the like is processed without necessity of attaching and detaching of mask and washing steps with respect to a workpiece in a fine blasting employing a fine abrasive. A negative pressure space (20) and an opposing negative pressure space (40) having openings (22, 42) are opposed by being spaced at a movement allowable interval of the workpiece such as a thin-film solar cell panel or the like and so as to face one side edge in the same direction as a moving direction of the workpiece. Then, a fine abrasive is injected from a blast gun (30) in which an injection hole (31) is disposed within the negative pressure space (20), the workpiece is relatively moved in a moving direction (T) with respect to the injection hole, and while the fine abrasive is injected, compressed gas generating a gas flow having a diffusing direction substantially parallel to the relative moving direction of the workpiece to carry out air blow, thereby the fine abrasive and a cut scrap injected from a space within each of negative pressure space through the intermediary of a suction device communicated with the negative pressure space (20) and/or the opposing negative pressure space (40).