A power transducer is downsized by reducing the size of a power source board and highly reliable. The power source board is provided in the power transducer and for a large-current circuit. The power transducer includes a power semiconductor module having lead terminals. Of the lead terminals provided for the power semiconductor module and connected with the main circuit board, predetermined one or ones of the lead terminals is or are connected with the main circuit board in the vicinity of a main circuit terminal stage and at a position or positions lower than the main circuit terminal stage. Alternatively, predetermined one or ones of the lead terminals is or are connected with the main circuit board at a position or positions lower than a position at which the main circuit terminal stage is provided.