To provide a plate material arranging system capable of easily forming a strong floor surface, and capable of naturally returning to a proper position even when an arranged plate material unit is dislocated by external force.

A plurality of guide rails 110 are arranged in the lateral direction in a state of becoming the longitudinal direction in the lengthwise direction. A plurality of plate material units 120 are longitudinally and laterally arranged on the guide rails 110 by forming a recess-projection in the shape of being mutually joined to a front face and a rear face. A plurality of plate material holding members 130 are slidingly supported in the longitudinal direction by the guide rails 110, and engage with the plate material units 120 from the front. A member energizing mechanism 140 individually energizes the plurality of plate material holding members 130 backward. Since arrangement of the plate material units 120 is maintained by energization of the member energizing mechanism 140, even if external force acts a little, the plate material units 120 are not dislocated, and naturally return to the proper position even if the plate material units are dislocated by the external force.