The condensed water treatment device obtains (S1) the storage water quantity (QW) of a condensed water tank, and drains (S4) condensed water in the condensed water tank when the storage water quantity (QW) is larger than a threshold value (tu) and also urea water is supplied to an exhaust passage for a selective-reduction type NOx catalyst. Thereby, the condensed water is neutralized and then drained to the outside of an internal combustion engine through the exhaust passage.
