To provide a rotary car washing brush directly and effectively using pressure of public city water originally held.

A conventional car washing method vainly releases hydraulic pressure of city water originally held, relies on other energy such as electricity for using a high pressure washing machine, or washing a car only by human labors. This invention not only solves the above-mentioned problems to significantly reduce car-washing time and labors, but also contributes to water-saving, effective use and saving of terrestrial energy, and global environments.