A method of sterilization by irradiating with ultraviolet rays with which it is possible to suppress effects on the human body and also to suppress an off odor generated after ultraviolet irradiation. The sterilization method has a step (a) that irradiates ultraviolet rays having a wavelength of 200-230 nm (inclusive) onto the skin of a finger or an arm and a step (b) that applies a topical skin formulation, cosmetic, or aqueous solution containing at least one amino acid or amino acid derivative selected from the amino acid group A to the region of skin irradiated by the ultraviolet rays. (Amino acid group A: valine, leucine, isoleucine, glutamic acid, arginine, serine, aspartic acid, proline, glycine).本發明係照射紫外線進行殺菌處理之方法，抑制對人體的影響，進而亦可抑制照射紫外線後產生的異臭。本殺菌方法係具有對手指或手臂的皮膚照射波長200nm以上230nm以下的紫外線之步驟(a)，與於經照射前述紫外線的前述皮膚之範圍，塗布含有選自以下胺基酸群A之至少一種胺基酸或胺基酸衍生物所構成之皮膚外用劑、化妝料或水溶液之步驟(b)。(胺基酸群A：纈胺酸、白胺酸、異白胺酸、麩胺酸、精胺酸、絲胺酸、天冬胺酸、脯胺酸、甘胺酸)
