A verification terminal includes a storage unit that stores partial block data. The partial block data is the latest data that a part of block data for update and addition in chronological order. The verification terminal selects a plurality of approval terminals to approve the partial block data stored in the storage unit. When a transaction included in the partial block data stored in the storage unit is updated by the verification terminal, the verification terminal transmits an approval request that requests the selected approval terminals to approve the updated partial block data to which the updated transaction and a hash value of the partial block data before updating are added. The verification terminal executes an update process of the partial block data based on approval results returned from the approval terminals in response to the approval request transmitted by the approval requesting unit.