PURPOSE: To prevent steam within a washing device from being discharged and washing effect of a printed circuit board to be improved by forming both external and internal tanks at each washing tank and by forming a slant surface which allows washing liquid collecting steam to flow constantly below the main unit of the washing device.

CONSTITUTION: An external tank 41 and an internal tank 42 are formed in a hot liquid washing tank 24 and a cold liquid washing tank 26. In the hot liquid washing tank 24, washing is performed by jetting a washing liquid 32 discharged from a discharge hole 44a of a pipe 44 to a printed circuit board 1 and washing is performed by the washing liquid 32 discharged from the discharge hole 44a while the entire printed-circuit board 1 is dipped into the washing liquid 32. Then, in the cold liquid washing tank 26, washing is performed by the same operation as in the hot liquid washing tank 24. In a steam washing tank 28, the washing liquid 32 cooled and condensed by the cold liquid washing tank 26 flows to the printed circuit board 1 which is located aslant for performing finish washing. Also, in the hot liquid washing tank 24, the washing liquid 32 which is overflown from a movable frame 43 flows into the outer tank 41 and is collected. It prevents steam of washing liquid from being discharged the outside.