Both-side polishing carrier and production method therefor

A both-side polishing carrier (10) comprising a base material (10a) the material of which is, for example, stainless steel (SUS) as is before, and a coating layer (10b) harder than the base material (10a) to cover the base material (10a). The coating layer (10b) is preferably one that is even in thickness for uniform coating and is not likely to be warped. The material of the coating layer (10b) of the both-side polishing carrier (10) is any one of diamond-like-carbon, nitride film, sapphire film and titanium nitride film. A method of producing the both-side polishing carrier (10) comprising the steps of providing a used both-side polishing carrier (10') used in polishing, and then coating the used carrier (10') with a coating layer (10b). The both-side polishing carrier can be rendered resistant to abrasion progress and provides sufficient thickness accuracy, film thickness distribution accuracy and surface roughness.