A data receiving part receives data transmitted from a plurality of measuring devices. A time determining part distinguishes management time from date and time of the data. The record generating part stores data of the same management time which are received during a predetermined acceptance time, in the same record. When un-arrived data belonging to the same management time exists at the end of the acceptance time, arrival of the un-arrived data is waited for during a predetermined wait time. Even if the data is arrived with some delay, arrival-delayed data can be stored in the same record. Thus, the missing data occurrence frequency can be suppressed.