An apparatus for preparing a cosmetic composition containing an emulsion substance formed by instant emulsification through a microfluidic channel is provided. The apparatus includes a housing defining the appearance of the apparatus and installed with a pump on one side, the pump being operated by a user； an external-phase chamber provided in the housing, and storing an external-phase fluid forming the external phase of the emulsion substance； a dispersed-phase chamber provided in the housing, and storing a dispersed-phase fluid forming the dispersed phase of the emulsion substance. The apparatus further includes a microfluidic channel providing a path for the external-phase fluid and the dispersed-phase fluid to flow for forming the emulsion substance by combining the external-phase fluid with the dispersed-phase fluid； and a tube for discharging the emulsion substance from the microfluidic channel.
