To provide a means for solving the problem in a conventional car washing machine wherein since a liquid wax is liable to flow, it is difficult to completely prevent the wax from adhering to a window pane.

An automobile is washed clean by an automatic washing machine, passed through a drying step, and passed through the drying step again at the same time or immediately after a window pane protective liquid is accurately jetted to a window pane portion in an area smaller than the entire area of the window pane, and then the wax liquid is applied to the other portions of a vehicle body while protecting the portion of the vehicle body covered with the protective liquid. Lastly, a solidified thin film 10 produced from the window pane protective liquid is removed since it can be easily removed by bare hand or with adhesive tape.