According to one embodiment, there is provided an anonymization system including at least one encryption apparatus, an anonymization apparatus, and a decryption apparatus. The encryption apparatus store personal data including one or more values for each item, and generates encrypted data from the personal data by encrypting the one or more values for each item included in the personal data. The anonymization apparatus generates encrypted anonymized data from the encrypted data without decryption by anonymizing one or more values for at least a portion of the items of the encrypted data. The decryption apparatus generates anonymized data from the encrypted anonymized data by decrypting the encrypted anonymized data.