Electric vehicles are being developed to help understand a decarbonized society. The generation of electromagnetic noise from switching operations is a concern with the electrification of vehicles. The noise is a reason for malfunctions in other devices, so, it is necessary to suppress it. Installing a filter circuit is one approach to reduce the noise level. Furthermore, as a result of the automatic operation, the number of functions will expand requiring the use of electronic components such as sensors. Due to the electrification of vehicles and the multi-functionalization of autonomous driving, the number of electronic components is on the rise. It is important to decrease the size of electronic components to secure space. Therefore, we examined the miniaturization of the filter circuit by combining an inductor and a capacitor. As a result, the gain features comparable to those of a typical filter circuit were attained, and the volume of the combined inductor and capacitor element was 2/3 that of a conventional filter circuit. By combining an inductor and capacitors, the volume of a filter circuit can be decreased while maintaining the gain features.