<p>A skin patch that can enhance the water resistance and handling easiness and can alleviate any irritation on the user. There is provided a skin patch comprising a flexible backing and, superimposed thereon, a plaster layer wherein the plaster layer contains a styrene-isoprene-styrene block copolymer and has a glass transition temperature (Tg) of -45° to -35°C and a tan .delta. (lag angle) value, determined at dynamic viscoelasticity measurement (frequency 6.2832 rad/s) at 45°C, of 0.25 or less.</p>
