To provide a preview control method for a program transmission system for attaining reduction of a preview time, effective utilization of a video transmission port in previewing or the like or price reduction of a video server.

In the preview control method for at least duplexed program transmission systems, raw materials of the respective systems are recorded in respective video servers, the preview of the raw materials recorded in the video server of the first system is then carried out, and the preview of the raw materials recorded in the video server of the remaining system is carried out during the idle time zone of the video server of the relevant system.