To enable a high degree of freedom with respect to change in kind and working conditions of a work, rapid change in working conditions of the work and the working excellent in accuracy by successively processing the work in plural working stages including coating stages with liquid coating materials, while allowing the work to travel around along a loop passing through these working stages, with an automated guided vehicle for horizontally holding the work, rotating it and conveying it.

This method comprises: horizontally holding a cylindrical substrate, i.e., work on an automated guided vehicle and fitting two flanges, each of which is to be attached to a chuck, to the both ends of the work, respectively with a robot, in a stage A; cleaning the work in a stage B; coating the cleaned work to form an undercoating layer on the substrate in a stage C; further coating the undercoated work to form a charge generation layer on the undercoating layer in a stage D; drying the resulting work in a stage E; successively processing the dried work in other stages F to I; and thereafter, removing the work thus processed from the vehicle in a stage J to return the vehicle to the original position in the stage A. At the time of allowing the automated guided vehicle to travel on a track, turntables 30 are placed at the four corners of a loop, respectively, to receive the vehicle and to turn the traveling direction of the vehicle by 90°. The position of the vehicle in the transverse direction with respect to its traveling direction is accurately controlled and the vehicle is allowed to travel at a constant speed, and if necessary, stopped. Thus, the positioning of the work is easily controllable and accurately performed, to enable practical continuous working of the work.