Provided is a novel material used to introduce an exogenous substance into cells. Also provided is a method for introducing an exogenous substance into target cells using this material. The present invention provides an exosome that is used to introduce an exogenous substance into target cells, wherein the exosome contains one type or two or more types of an exogenous substance and a substance that induces macropinocytosis in the target cells. The present invention also provides a composition containing the exosome and a method for introducing an exogenous substance into cells using this exosome.
