A stream data management method includes: storing in a sequence header of the top original moving image information a terminal ID indicating a terminal which generated original moving image information and date-and-time information which is guaranteed by a third party, storing in a sequence header of the next original moving image information a characteristic value of the last partial information of the preceding original moving image information, generating signature-related information of the original moving image information, generating cutout moving image information to which a sequence header is added, generating signature-related information of the cutout moving image information, and verifying originality and actual time of cutout stream data based on the cutout moving image information, the signature-related information of the cutout moving image information, and the signature-related information of the original moving image information.