Because conventional switching converters have been usually using unbalanced circuit topologies, parasitice between the drain/collertor of an active switch and frame ground through its heat sink may generate the commom-mode conducted noise. We have proposed a balanced switching converter circuit, whitch is an effective way to reduce the commom-mode converter version of the balanced switching converter was presented and the mechanism of the commom-mode noise reduction was explained using equivalent circuits. This paper extends the concept of the balanced switch converter circuit and presents a buck-boost converter version of the blanced switching converter. The feature of common-mode niose reduction is confirmed by experimental resuits and the mechanisem of the commom-mode niose reduction is explained using equivalent circuits.