To provide a tray conveyance system having high conveyance efficiency in a conveying means in which one or a plurality of trays are stacked and placed.

The tray conveyance system comprises a tray in which plate works are loaded one by one, and a conveying device to convey one or a plurality of the stacked trays, and a speed control means changes the conveying speed patterns L1, L2 according to the number of trays to be conveyed by the conveying device. The acceleration in an accelerated or decelerated state is higher in a case in which control is performed following a solid line L1 than that in a case in which control is performed following a one-dot-chain line L2. Further, the maximum speed is higher in a case in which control is performed following the solid line L1. When the number of trays is large, the acceleration on the entire conveying device can be reduced by controlling a traveling truck following the one-dot-chain line L2, and considerable vibration of the conveying device can be prevented. On the other hand, when the number of the trays is small, the time for movement to a destination can be shortened by controlling the traveling truck following the solid line L1.