To provide a flexible substrate which has adhesiveness required for a process of dicing the board into pieces and permits a subsequent peeling process to be easily performed.

The flexible substrate, which is used by being peeled from a supporting substrate, includes a first adhesive flexible material layer 11 and a second adhesive flexible material layer 12 whose adhesiveness is weaker than that of the first adhesive flexible material layer 11. A surface in contact with the supporting substrate 20 is made of the first and second adhesive flexible material layers. The first adhesive flexible material layer 11 is located near a cutting plane and further surrounds the neighborhood of the cutting plane.