Fentanyl-containing patch for external use

A patch for external use which has a laminate structure comprising a substrate and a pressure-sensitive adhesive layer which contains a styrene/isoprene/styrene block copolymer as the base and further contains a tackifier resin consisting of a rosin resin and at least one other tackifier resin, a softening agent consisting of polybutene and liquid paraffin, a fatty acid ester, and fentanyl, characterized in that the weight ratio of the rosin resin to fentanyl is 1 to 5, the weight ratio of the rosin resin to the whole tackifier resin is 0.1 to 0.6, and the tackifier resin accounts for 30 to 60wt % of the whole pressure-sensitive adhesive layer. The patch is excellent in the permeation of fentanyl through the skin and in storage stability, and is weak in irritation to skin.