The present disclosure provides a method and apparatus for subband-coding a frequency conversion unit and a video encoding/decoding method a video encoding/decoding apparatus using the same. The method and the apparatus for subband-coding the frequency conversion unit include generating an encoding stream by splitting the frequency conversion unit into one or more frequency domains, generating frequency domain encoding information according to whether there is a non-zero frequency coefficient in each frequency domain, scanning the frequency coefficient of each frequency domain to generate a frequency domain frequency coefficient stream, and binarizing and encoding the frequency domain encoding information and the scanned frequency domain frequency coefficient stream.