To apply surface treatment to an outer surface of a development sleeve to be rough-surfaced so as to restrict deterioration of development agent carrying quantity due to aging, and prevent irregularities in images.
In this surface treatment device, the development sleeve as a subject to be processed and wire material 65 are stored in a storage tank, a rotary magnetic field is generated, and the wire material 65 is collided with the outer surface of the development sleeve to be rough-surfaced. The wire material 65 is composed of austenite-based stainless steel or martensite-based stainless steel. The wire material 65 is formed columnar. Outer diameter D of the wire material 65 is 0.5 mm or more, and 1.2 mm or less. With total length L, the wire material 65 has L/D of 4 or more and 10 or less. Outer edge parts 65a provided at both length end parts of the wire material 65 are chamfered to have a circular arc-shaped section. Radius of curvature R of the section of the outer edge part 65a is 0.05 mm or more and 0.2 mm or less.