A nanofiber for an air filter and a method for manufacturing the same are proposed. The nanofiber may include a styrene-(meth)acrylate-acrylonitrile random copolymer having a zwitterionic functional group in a side chain. The nanofiber can greatly enhance the bonding of particulate matter (PM) particles with the surface of a polymer by having a high dipole moment derived from the zwitterionic functional group, thereby providing high efficiency of filtration (>99.9%) of the PM particles. Furthermore, the nanofiber can be very usefully used as a core material for air purifier filters and vehicle air purification filters by having low airflow resistance and excellent antibacterial properties.