Disclosed are a cloud service system, a cloud service device, and a method using same. When a download of a shared original content is requested, a conversion factor is determined by considering device information and network information of a terminal device requesting the download, and converted content is provided, wherein the content of the converted content has been converted based on the determined conversion factor. The conversion factor is calculated by applying an application ratio to a base conversion factor. As a result, downloading time can be reduced, network traffic can be reduced, and saving space on a terminal can be efficiently managed.