Provided is a method of file synchronizing. The method includes: determining whether there is a changed matter in a file which is divided into a plurality of chunk files; calculating a hash value for each of plurality of divided chunk files when it is determined that there is a changed matter in file; transmitting a hash value list configured by calculated hash values to a server; receiving a transmission request for a chunk file corresponding to a hash value which is not stored in server, among hash values included in hash value list; and transmitting chunk file to the server in response to the transmission request.