PURPOSE: To make car washing work pleasant and attain water saving by discharging car wash water only onto the washed face with a car mop applied thereto in the case of using the car mop so as not to perform car washing while dragging a water hose.

CONSTITUTION: The tip discharge port outer diameter parts 9 of a water discharge tube 2 crossing at the center part are provided with water discharge nozzle tube connecting parts opened thereto in the longitudinal and lateral dimensional positions coinciding with body underfloor contour parts, and a feed water connecting cylinder 8 is installed in a dimensional position coinciding with the body underfloor contour part. There is also provided an L-shape water discharge nozzle tube equipped with a water discharge nozzle part 3 and a water plug 4 at its tip part. Such a device is fixedly laid at the body underfloor surface or embedded in the body underfloor to obtain a car wash water discharge device.