To provide a processing system of a substrate, in which adhesion of dust to the substrate can be prevented as much as possible at the time of irradiating amorphous silicon with an Xe-Cl excimer laser beam.

A movable substrate stage 32 for mounting a substrate 21 deposited with amorphous silicon is disposed in a processing chamber 31a. Amorphous silicon of the substrate 21 mounted on the movable substrate stage 32 is irradiated with an Xe-Cl excimer laser beam B by a beam irradiating means. Each inner face of the processing chamber 31a is applied with a processing chamber viscous material 34 having viscosity. Dust floating in the processing chamber 31a adheres to the processing chamber viscous material 34 and adhesion of dust to the substrate 21 can be prevented as much as possible.