One end of a bus bar for leading an output voltage output from a switching power supply to the outside is a connection terminal connected to an output end associated with the switching power supply, while the other end is an output terminal VO. A ferrite core has a through-hole through which the bus bar is disposed. Electromagnetic coupling from the switching power supply is suppressed between the output terminal VO of the bus bar and at least a part of the ferrite core on the output terminal VO side along the bus bar. In this way, electromagnetic coupling of a part of a choke coil including the ferrite core with the bus bar penetrating therethrough on the output terminal VO side and the switching power supply is suppressed, whereby propagation of noise to the output terminal VO is suppressed.