A semiconductor package has: a semiconductor chip having first and second main electrodes arranged on two principal surfaces being opposite to each other; a first main wiring plate connected to the first main electrode and having a first external connection terminal; a second main wiring plate connected to the second main electrode and having a second external connection terminal; a first shell connected through an insulating film to at least a part of a second principal surface of the first main wiring plate, the second principal surface of the first main wiring plate being opposite to a first principal surface of the first main wiring plate that is connected to the first electrode; and a second shell connected through an insulating film to at least a part of a second principal surface of the second main wiring plate, the second principal surface of the second main wiring plate being opposite to a first principal surface of the second main wiring plate that is connected to the second electrode. The first principal surfaces of the first and second main wiring plates are adjacent to and parallel to each other except at the locations where the first and second main wiring plates are connected to the semiconductor chip and the locations where the first and second external connection terminals are formed.