Abstract: A host computer is used to enter into a measuring apparatus to be leased, a contracted term of lease and the date when the lease starts, and/or a contracted number of times the measuring apparatus can be used, and the warning time when a warning message should be given. After the warning time, the warning message is displayed. When the contracted term of lease expires or when the measuring apparatus has been used the contracted number of times, a message notifying the user of the expiration of the lease is displayed and/or the functions of the measuring apparatus are disabled.