A method for manufacturing a multi-piece substrate includes preparing a first frame having a connecting portion to which a first piece substrate is to be connected, forming on a portion of the first piece substrate connected to a second frame a conductive pattern having a contour corresponding to the periphery of the connecting portion of the first frame, irradiating laser along the boundary between the second frame and the conductive pattern on the first piece substrate such that the first piece substrate having a joint portion which engages with the connecting portion of the first frame is detached from the second frame, and fitting the joint portion of the first piece substrate into the connecting portion of the first frame such that the first piece substrate is connected to the first frame.