Abstract: A common-mode noise filter is provided, and comprises a first transmission structure and a second transmission structure. At least one first transmission unit is connected between a first signal input end and a first signal output end of the first transmission structure in series. At least one second transmission unit is connected between a second signal input end and a second signal output end of the second transmission structure in series. Two first capacitors are connected between the first signal input end and the second signal input end in series, and connected at a first node together. A first common-mode noise suppression unit is connected between the first node and a reference potential, and comprises a second capacitor and a first lossy element connected to the second capacitor in series or parallel. The first common-mode noise suppression unit can absorb a common-mode noise via the first lossy element.