A power converter includes a shunt resistor constituted by a shunt resistance and a plurality of main electrodes made of a sheet-like resistive material. In the shunt resistor, plates lower in volume electric resistivity than the resistive material, higher in thermal conductivity than the resistive material and thicker in thickness than the resistive material are fixedly attached by solder, to the side surfaces of the main electrodes opposite to the side surfaces with which the main electrodes are fixedly attached to an insulating layer. At least one plate main electrode for electrically connecting with main circuit wiring is provided in each of the plates. At least one constricted portion is formed between each of the plate main electrodes and the shunt resistance. Plate detection electrodes for detecting a voltage between the opposite ends of the shunt resistance is provided on the plates near the shunt resistance portion.