An adhesive skin patch provided with a support and an adhesive agent layer laminated on at least one surface of the support, wherein the adhesive agent layer contains at least one component selected from the group consisting of fentanyl and a salt thereof, an adhesive base material, and an antioxidative agent having a sulfur atom in the molecule thereof.本發明係一種貼附劑,其係具備支持體、及積層於該支持體之至少一面之黏著劑層者,且上述黏著劑層含有選自由芬太尼及其鹽所組成之群中之至少一種、黏著基劑、及分子內具有硫原子之抗氧化劑。