To provide such a measuring instrument as reducing a corresponding load in a center-side system without causing warning or preannouncing communications to center by providing a communication date/hour control means to a measuring instrument having a certification term expiration warning function, the control means allowing a date and hour (calling date and hour) to be set at an optional date and hour for making a warning or preannouncing communication.

In this measuring instrument such as a flow meter 1, a present date of a calendar means 15 is compared with a certification term expiration date stored in a certification term storage means 16 by using a comparison means 17. Where a prescribed time comes prior to the expiration date, or where the expiration date has passed, preannouncing information on certification term expiration or warning information is communicated with the exterior by a communication means 14 at an optional date and hour determined by a communication date/hour control means 18. The optional date and hour are determined by using random numbers or determined from a value specific to the flow meter, such as a production number.