Semiconductor device comprising semiconductor power elements

A semiconductor device is provided comprising main electrodes (M10, M20, M30) aligned along the length of a resin case (1). The main electrodes (M10, M20, M30) each have an inside main surface facing the inside of the case body (101) in which insulating substrates (3A, 3B) are provided. The outside main surface faces opposite to the side where the insulating substrates (3A, 3B) are provided. A conductor (4) is so disposed as to be opposed to the outside main surfaces of the main electrodes (M10, M20, M30). This configuration of the semiconductor device enables reduction of the self-inductance without parallel arrangement of the main electrodes, achieves a high switching characteristic and ensures a stable operation and high reliability.