PURPOSE: To prevent a following washed vehicle from clashing against a front washed vehicle from behind by stopping a conveying device through a control device when it is detected that the washed vehicle stops in a conveying section longer than fixed time.

CONSTITUTION: A vehicle 7 is carried into an installation type car washing machine body 2 from its front side, and roller conveyors 3a, 3b to carry out the vehicle 7 behind the car washing machine body 2 are installed. The carrying out sections of the roller conveyors 3a, 3b are provided with safety shelves 24a, 24b, which are severally provided with photoelectric switch 29 to detect the vehicle 7 located in the carrying out section. In the case where the vehicle 7 is stalled in the carrying out section on account of a trouble, the photoelectric switch 29 detects the vehicle 7 longer than a fixed time. A control device 34 therefore urgently stops the rear conveyors 21a, 21b of the roller conveyors 3a, 3b, middle conveyors 20a, 20b and front conveyors 19a, 19b. A next carried vehicle 36 can thereby be prevented from clashing against the preceding vehicle 7 from behind.