To start the operation of a measuring instrument without manual operation when a power source is turned off and thereafter, it is turned on.

The measuring system is provided with an operating terminal, an operating mode setting part setting either a continuous measurement mode or a maintenance mode based on the command from this operating terminal, the measuring instrument activated by either the continuous measurement mode or the maintenance mode corresponding to the signal from this operating mode setting part, a non-volatile memory memorizing the operating mode at that time when the power source is turned off during the activation of this measuring instrument, and the measuring device activated by the operating mode memorized in the non-volatile memory when the power source is turned on. In the case when the power source is turned on, the operating mode is memorized into the non-volatile memory from the final control element, and then the operating mode setting of the operating mode setting part is done based on this memorized operating mode.