In an electric power conversion/inversion apparatus, including, such as an inverter therein, for obtaining reduction in circuit inductance and wiring resistance therein by bringing small as a whole, having good installability and high reliability and efficiency of electric power conversion, as well, semiconductor chips 1 are disposed, being put between a positive input bus bar 14p and a negative input bus bar 14n and plural output bus bars 18 at crossing positions thereof, and are connected electrically and thermally, to the positive input bus bar 14p in a pole direction consistent therewith while to the negative input bus bar 14n in a pole direction consistent therewith, and further to the common output bus bars 18 in pole directions being different from side by side.