Abstract A new database system for the JT-60SA tokamak has been developed. This system meets the following requirements: to hold all the JT-60SA data and prevent loss of data, to allow researchers to use data without knowing internal database configuration and structure, to manage data revision so that stored data can be traced back to the older revision anytime. Depending on the timing of data transfer for storage or reference, the experiment data are categorized into three types: (i) discharge data, (ii) plant monitoring data, and (iii) unprocessed data. In the first step in constructing a new database system, we have designed the basic structure of the JT-60SA database system to manage all three data types. The dedicated tools for data transfer or retrieval prevent unregistered computers from accessing the experiment data. The RAID6 configuration of a hard disk drive (HDD) and the magnetic tapes improve data reliability. This paper reports details about the functions of the new JT-60SA database system. Furthermore, the elapsed time of data transfer and storage is measured to evaluate the performance of the JT-60SA database system. It takes 20 s to transfer and store 6 GB of data, which is enough to meet the required performance.