To solve the problem of being economically irrational in buying a new fully automatic washer only for a countermeasure against water leakage in washing for a home using the fully automatic washer due to predicting damage as large when the water leakage is caused in the washing since a conventional fully automatic washer does not take the countermeasure against an overflow of waste water and the water leakage to the downstairs by clogging of a drainage ditch though the fully automatic washer is already spread to almost all homes.

This mechanism stops the waste water by independently sensing the water leakage from the washer, and prevents the water leakage in the washing by additionally installing this mechanism to an existing washer.