A workpiece information recognition system comprising: a workpiece placing tool capable of placing a workpiece; a reference object detachably provided on the workpiece placing tool; an information detector configured to detect information about the reference object; and a control device configured to receive the information about the reference object from the information detector, wherein the control device includes: a storage configured to store data on a relationship between the information about the reference object and information about the workpiece; and a controller configured to recognize the information about the workpiece placed on the workpiece placing tool by checking the information about the reference object detected by the information detector with the data stored in the storage, the reference object is a solid, the workpiece placing tool includes a base plate having a planar shape, the reference object has a convex shape protruding from the base plate, the information about the reference object includes information about a shape of the solid when seen in planar view of the base plate, and the solid has a different shape depending on the information about the workpiece placed on the workpiece placing tool. a workpiece placing tool capable of placing a workpiece; a reference object detachably provided on the workpiece placing tool; an information detector configured to detect information about the reference object; and a control device configured to receive the information about the reference object from the information detector, wherein the control device includes: a storage configured to store data on a relationship between the information about the reference object and information about the workpiece; and a controller configured to recognize the information about the workpiece placed on the workpiece placing tool by checking the information about the reference object detected by the information detector with the data stored in the storage, the reference object is a solid, the workpiece placing tool includes a base plate having a planar shape, the reference object has a convex shape protruding from the base plate, the information about the reference object includes information about a shape of the solid when seen in planar view of the base plate, and the solid has a different shape depending on the information about the workpiece placed on the workpiece placing tool. a storage configured to store data on a relationship between the information about the reference object and information about the workpiece; and a controller configured to recognize the information about the workpiece placed on the workpiece placing tool by checking the information about the reference object detected by the information detector with the data stored in the storage, the reference object is a solid, the workpiece placing tool includes a base plate having a planar shape, the reference object has a convex shape protruding from the base plate, the information about the reference object includes information about a shape of the solid when seen in planar view of the base plate, and the solid has a different shape depending on the information about the workpiece placed on the workpiece placing tool.