When a viewer views content, it is reproduced by a reproduction procedure depending on a dynamic condition set in the content. Here, a content object data input unit obtains an externally-input content object. The content object is stored in a content object data retention unit, if necessary. The content object includes a reproduction rule and a content data. A reproduction rule evaluation and execution unit obtains the reproduction rule in the content object and performs processing in accordance with the reproduction rule. The reproduction unit reproduces a reproducible data specified by the reproduction rule evaluation and execution unit. An identifier management unit retains an identifier of a content object reproduction device and provides the identifier upon request. It is thus possible to reproduce in accordance with the reproduction rule set in the content object data and to control the reproduction procedure depending on the dynamic condition.