Abstract: A method of heterogeneous reaction is described, comprising reacting a water-soluble component and an oil-soluble component dispersed in the water-soluble component or an aqueous medium containing the same. This dispersion is attained by passing the oil-soluble component through the micropores of a hydrophilic material as it is introduced into the aqueous medium. This hydrophilic material can be shaped into a desired form such as a membrane and a fabric. The flow rate, reaction rate and conversion are easy to control in the present method since the particle size of the oil-soluble component can be appropriately controlled. Furthermore, the present method does not need any stirring power nor an emulsification operation, and thus is advantageous from an economic standpoint.