To provide a database converting system whereby a database requiring the conversion of data form is automatically detected and the form conversion of data added in the detected database is dynamically executed without stopping normal processing such as an on-line processing, etc.

This system is provided with a database access part 22 detecting access to the database 32 by the new data form and a database converting part 24 converting data added in the old before-conversion database 30 into data by the different data form so that the database 32 is automatically and newly generated without stopping the system when an access request as against the database 32 is detected for the first time and access is performed for the database 32 by the new data form after conversion at the point of time when generation is executed.