The present invention provides a music purchasing/transfer system allowing contents to be acquired in a remarkably efficient manner. In the system, a content acquisition apparatus, and method and program thereof are provided. The apparatus includes a content storage section used for storing contents; an output section for outputting the identification of every content that can be presented by a content providing apparatus for presenting contents; and a content acquisition section for acquiring a content, which is identified by a content identification selected by carrying out an operation to select one of identifications output by the output section, from the content providing apparatus, wherein the output section outputs identifications of contents not stored yet in the content storage section as identifications different from other identifications output as identifications of other contents already stored in the content storage section.