Even when a substrate on which a semiconductor package has been mounted is made curved, stress upon electrical connections is mitigated, thereby eliminating faulty connections and improving connection reliability. A semiconductor chip has electrodes on a second face thereof. Support blocks, capable of bending and flexing, are placed at two locations on a peripheral edge of a first face of the semiconductor chip. An interposer is placed so as to span the support blocks with the support blocks interposed between itself and the semiconductor chip, and has a wiring pattern in a flexible resin film. Two end portions of the interposer are folded back onto the side of the second face of the semiconductor chip, and the wiring pattern thereof is electrically connected to the electrodes of the semiconductor chip.