A motor-driven compressor includes an inverter device. The inverter device includes a noise reducing unit. The noise reducing unit includes common-mode choke coils and a smoothing capacitor. The common-mode choke coils include a first coil and a second coil. The first coil includes a first core, a first winding, and a second winding. The first core includes a first straight portion and a second straight portion. The second coil includes a second core, a third winding, and a fourth winding. The second core includes a third straight portion and a fourth straight portion. The first coil and the second coil are arranged side by side such that a current flowing through the first winding and the third winding generates an annular magnetic flux that passes through both of the first straight portion and the third straight portion.