PURPOSE: To realize re-extraction of data while direct storage is being reduced by providing a data storage management section and an auxiliary storage section in the data switching exchange.

CONSTITUTION: A data storage management section 11 receiving a data registration request, a data extract request or a data re-extract request of a user program 19 manages the registration, extraction and re-extraction of the data. A data storage management section 14 extracts and replies data to the data storage management section 11 based on the storage or extract request of data. In this case, data of a data storage state storage section 13 and a data storage definition storage section 15 are referenced and even after the data are registered and extracted, data are not deleted but left as reserved data, then even when the user program is extracted, the data are extracted again. Moreover, a storage data storage section 18 and a data storage management section 16 storing storage data to an auxiliary storage device as storage data and part of the stored data is stored automatically in the auxiliary storage, the re-extraction of data is realized.