An information processing device comprising: content storing means for storing a content; communication means for receiving, from a preceding device or a request source, and transmitting a request message that includes information indicating the request source that requests the content, a request condition that is a condition for determining the content that is a target of request, and a request-source-stored-content that includes information of a content stored by the request source; request determination means for determining a content that satisfies the request conditions and is not included in the request-source-stored-content in the contents stored in the content storing means; and request message processing means for, when the content is determined to satisfy the request conditions and determined to be not included in the request-source-stored-content of the request source, updating the request-source-stored-content in the request message by adding information relating to the determined content to the-request-source-stored-content; wherein when the content is determined to satisfy the request conditions and determined to be not included in the request-source-stored-content of the request source, the request determination means is configured to transmit the determined content to the request source via the communication means, and to transmit the updated request message to a next device via the communication means; and wherein when the content is determined not to satisfy the request conditions, or is determined to be included in the request-source-stored-content of the request source, the request determination means is configured to transmit the request message via the communication means, without update of the request-source-stored content in the request message, to a next device. content storing means for storing a content; communication means for receiving, from a preceding device or a request source, and transmitting a request message that includes information indicating the request source that requests the content, a request condition that is a condition for determining the content that is a target of request, and a request-source-stored-content that includes information of a content stored by the request source; request determination means for determining a content that satisfies the request conditions and is not included in the request-source-stored-content in the contents stored in the content storing means; and request message processing means for, when the content is determined to satisfy the request conditions and determined to be not included in the request-source-stored-content of the request source, updating the request-source-stored-content in the request message by adding information relating to the determined content to the-request-source-stored-content; wherein when the content is determined to satisfy the request conditions and determined to be not included in the request-source-stored-content of the request source, the request determination means is configured to transmit the determined content to the request source via the communication means, and to transmit the updated request message to a next device via the communication means; and wherein when the content is determined not to satisfy the request conditions, or is determined to be included in the request-source-stored-content of the request source, the request determination means is configured to transmit the request message via the communication means, without update of the request-source-stored content in the request message, to a next device.