PURPOSE: To provide a surface polishing device of a metal layer stuck on substrate which can accomplish a necessary satin finish surface easily in a mass production and ecconomically.

CONSTITUTION: A closed area forming body structure 9 where the main surface of the metal layer of a substrate 8 with metal layer stuck on loaded and conveyed on a conveying mechanism 7 is opened and a closed area is formed is provided. Inside the closed area forming body structure 9, a magnetic abrasive powder spraying means to spray a high pressure gas in which a magnetic abrasive powder is dispersed and included, to the main surface of the metal layer, and a gas exhaust means having successive suction ports to suck a gas including the sprayed magnetic abrasive powder and the shavings of the metal layer are provided. A separating/collecting means to separate and collect the magnetic abrasive powder in the sucked gas by an exhausting means is also provided. Consequently, the generation of a polishing unevenness owing to the attachment of the magnetic abrasive powder can be reduced or prevented easily, and even when the magnetic abrasive powder is reused, the same polishing process can be accomplished.