To display data that users request, immediately without remeasuring, avoiding waste of memory resources.

A data containing means for containing data concerning measurement, a data conversion means converting data concerning the measurement contained in the data containing means and producing converted data and a display means for displaying the converted data are provided. The display means transmits an acquisition request of the converted data to the data conversion means. The data conversion means, upon receiving the acquisition request of converted data from the display means, acquires and converts the data concerning the measurement contained in the data containing means accordingly to the received acquisition request. By providing the produced converted data to the request source display means, the above problems are resolved.