A gas sulfur trioxide continuous sulfonation production device is provided with a sulfur trioxide generator, a raw material storage tank, an absorption tower, a venturi tube-type reactor, a kettle-type reactor, a reactant first storage tank and a reactant second storage tank, and has the advantages that a raw material liquid and sulfur trioxide can be subjected to full mixing reaction in the venturi tube-type reactor, and the utilization rate of sulfur trioxide can be increased; through controlling the flow quantity of the raw material liquid, the product quality can be stabilized; after a gas-liquid mixture entering the kettle-type reactor is subjected to continuous reaction, an excess part overflows to the reactant storage tanks, a sulfonated material is sent to a next working procedure processing device from a discharge port of the reactant second storage tank, the device is allowed to perform continuous production, the production efficiency is high, acid slag generated in the reaction can be discharged through slag discharge valves, and the device is suitable for a slag or slagless sulfonation reaction; and a disc-type stirrer can smash sulfur trioxide bubbles in the kettle-type reactor, sulfur trioxide and the raw material liquid are fully and continuously mixed, and the utilization rate of sulfur trioxide is further improved.