A personal information management system, comprising: a blockchain server configured to store a blockchain including, for each block, a transaction and a transaction ID for identifying the transaction; and a personal information management apparatus configured to access the blockchain server, wherein the personal information management apparatus is configured to store a second piece of personal information on an individual, which accompanies a first piece of personal information for identifying the individual, in association with a first transaction ID received from the blockchain server, wherein the personal information management apparatus is configured to transmit the first transaction ID associated with the second piece of personal information to the blockchain server, delete the second piece of personal information and the first transaction ID, and store, after having transmitted the first transaction ID, a second transaction ID received from the blockchain server, wherein the blockchain server is configured to generate the first transaction ID, generate a first block including a first piece of converted data which is based on the first piece of personal information and the first transaction ID, add the first block to the blockchain, and transmit the first transaction ID to the personal information management apparatus, and wherein the blockchain server is configured to in response to receiving the first transaction ID from the personal information management apparatus generate the second transaction ID, generate a second block including the first piece of converted data and the second transaction ID, add the second block to the blockchain, and transmit the second transaction ID to the personal information management apparatus. a blockchain server configured to store a blockchain including, for each block, a transaction and a transaction ID for identifying the transaction; and a personal information management apparatus configured to access the blockchain server, wherein the personal information management apparatus is configured to store a second piece of personal information on an individual, which accompanies a first piece of personal information for identifying the individual, in association with a first transaction ID received from the blockchain server, wherein the personal information management apparatus is configured to transmit the first transaction ID associated with the second piece of personal information to the blockchain server, delete the second piece of personal information and the first transaction ID, and store, after having transmitted the first transaction ID, a second transaction ID received from the blockchain server, wherein the blockchain server is configured to generate the first transaction ID, generate a first block including a first piece of converted data which is based on the first piece of personal information and the first transaction ID, add the first block to the blockchain, and transmit the first transaction ID to the personal information management apparatus, and wherein the blockchain server is configured to in response to receiving the first transaction ID from the personal information management apparatus generate the second transaction ID, generate a second block including the first piece of converted data and the second transaction ID, add the second block to the blockchain, and transmit the second transaction ID to the personal information management apparatus.