Provided is an emulsion production apparatus wherein production and consumption of emulsion can be carried out continuously, capacity of a tank can be reduced and production cost can be reduced by eliminating the need for a mixing machine. An emulsion production apparatus comprises a main tank (10) in which a main space (12) is formed, and a sub-tank (16) in which a space (18) communicating with the main space (12) and promoting emulsification is formed. A circulation interconnection passage (28) interconnects the main space (12) and a first negative pressure mixer (22). The first negative pressure mixer (22) is provided in the space (18) for promoting emulsification, and emulsion is introduced into the first negative pressure mixer (22) via the circulation interconnection passage (28). Water, fuel and emulsifier are sucked into the first negative pressure mixer (22) by a negative pressure generated therein, and transformed into emulsion. Emulsification of emulsion is promoted by injecting emulsion in the first negative pressure mixer (22) into the space (18) for promoting emulsification of the sub-tank (16), and then the emulsion is introduced into the main space (12).