The present invention has an objective to easily obtain an emulsion exhibiting superior storage stability, and in particular, an emulsion of a polyorganosiloxane. The present invention provides a method for producing an emulsion characterized by obtaining an emulsion by emulsifying a mixture of an oil and a surfactant, obtained by synthesizing the surfactant in the oil. In particular, the method is suitably used for the preparation of an emulsion of an organopolysiloxane (A) which is usually difficult to be stably emulsified. A silicone-based surfactant (B), and in particular, a silicone-based surfactant having a small degree of polymerization of a siloxane chain such as a trisiloxane is synthesized in an oil. Thereby, an emulsion exhibiting superior storage stability can be produced.