A capacitor module that smooths a voltage of an inverter circuit includes a supply assembly including a connection terminal to the inverter circuit, an alternating-current assembly including a capacitor and a first bus bar, and a direct-current assembly including a second bus bar connecting a DC power source and the supply assembly. The alternating-current assembly and the direct-current assembly are side by side in a plan view and one side view of the capacitor module, and are arranged with the side surfaces thereof opposing each other in an opposite side view. The supply assembly is located inside an outer peripheral region collectively surrounding both the alternating-current assembly and the direct-current assembly in the plan view.