Provided is an external preparation composition containing S-flurbiprofen and peppermint oil as a transdermal absorption promoting agent, the external preparation composition suppressing a decrease over time in the S-flurbiprofen content, and exhibiting excellent S-flurbiprofen storage stability. An external preparation composition containing S-flurbiprofen and peppermint oil as a transdermal absorption promoting agent, the external preparation composition including the formulation of one or more types selected from a group consisting of an ester in which two medium chain fatty acids are bonded to propylene glycol, and an ester in which three medium chain fatty acids are bonded to glycerine.
