PURPOSE: To enable the floor face of a car-wash system having car wash lanes, a car way to each car wash lane, and a feeding mechanism for washings to be constructed easily in a short time by laying panels over each car wash lane for the formation of the floor face of the car wash lane, and forming an antislip surface as part of the floor face.

CONSTITUTION: A coin-operated car wash 1 has an administrative office 3 installed adjacent a car entrance 4 and within a sectioned site 2 and has right and left car-wash lanes 6 installed behind the office with a car course 5 between them, and a feeder for washings is installed in each car wash lane 7. In this case, the floor portion 11 of the car wash lane 7 comprises a horizontally supporting skeleton 21 and a rectangular steel plate placed over the skeleton 21. A floor face constructed of a steel plate is installed, with a water gradient provided from its front to rear end, and has a drainage ditch 31 formed at the rear end. Also, a pair of antislip surface portions having finely dented steel plates bonded to their surfaces are provided on the floor face.