PURPOSE: To provide an electrodeposition coating device capable of reducing the total running cost by making the electrode soln. controller economical.

CONSTITUTION: A membrane device 2 provided in an electrodeposition tank 1 and an electrode soln. tank 3 for controlling the conductivity of the soln. are connected through an electrode soln. discharge pipeline 4 and an electrode soln. feed pipeline 5. A stop valve 17 closed when powder supply is stopped and opened when powder supply is resumed is provided to a pipeline 10 for drawing off a part of the soln. from the tank 3. Meanwhile, a cushion tank 18 is furnished adjacent to the tank 3, and the cushion tank and the electrode soln. tank 3 are communicated at their upper parts. Further, a stop valve 20 closed when powder supply is stopped and opened when powder supply is resumed is furnished to a bypass pipeline 21 connecting the cushion tank 18 and soln. feed tank 5, the surplus clean electrode soln. is accumulated in the cushion tank 18, and the accumulated soln. is effectively utilized as a circulating electrode soln. when coating is resumed.