A supercharger with an electric motor includes, a turbine impeller rotationally driven by an exhaust gas, a compressor impeller rotationally driven by rotation of the turbine impeller, a compressor housing accommodating the compressor impeller, a turbine housing accommodating the turbine impeller, a shaft coupling the turbine impeller and the compressor impeller, a bearing housing rotatably supporting the shaft, an electric motor accommodated in an inside of the bearing housing for assisting rotation of the turbine impeller, and a power supply line extending from an inside to an outside of the bearing housing. The power supply line has one end portion connected to the electric motor, and the other end portion connected to a connector that receives electric power. The connector is installed at a position that is away from a side of the turbine impeller, and is less affected by heat of the exhaust gas.