To suppress the elution of sulfur contained when the surface of the stainless steel is worked, though stainless steel, particularly, sulfur based free-cutting stainless steel such as SUS303 and SUS430 having a high sulfur content for securing free-cutting properties is used.

For surface treatment for stainless steel, the surface of the stainless steel is subjected to shot blast treatment. Then, the surface of the stainless steel is subjected to passivation treatment. In this way, the content of sulfur in the surface is made low, and also, a protective film is formed, thus the elution of sulfur in a liquid can be suppressed.