Provided a method of sterilization by ultraviolet irradiation whereby effects on the human body can be mitigated and an odor that arises after ultraviolet irradiation can be controlled. The sterilization method includes: a step (a) of irradiating a skin of a hand or arm with ultraviolet having a wavelength of 200 nm or more and 230 nm or less; and a step (b) of applying a topical skin preparation, cosmetic, or aqueous solution containing at least one amino acid or amino acid derivative selected from an amino acid group A to a region of the skin irradiated with the ultraviolet. The amino acid group A includes valine, leucine, isoleucine, glutamic acid, arginine, serine, aspartic acid, proline, and glycine.