To provide a portal car washing machine in which a driving motor for driving car washing tools can be controlled with precision by use of a movement sensor capable of accurately measuring the amount of movement of a car washing machine main body, even if the diameters of wheels vary because of wear of if the wheels idle because of slip.

In portal car washing machine which includes a rail 2 laid on a site, a car washing machine main body 3 moved on the rail 2 by a moving motor, car washing tools 4, 5, 6 provided on the car washing machine main body 3 and driven by a driving motor, a car sensor 8 and a movement sensor 12 which are provided in the car washing machine main body 3, and a control device controlling the driving motor according to signals of both of the sensors 8, 12, magnets 11 are provided on the rail 2 at equal intervals, and the movement sensor 21 is a magnetic sensor that detects the magnets 11.