To prevent rate account for a prolonged time by always monitoring a package, grasping an exchange fault in short time and reflecting it on rate account.

A rate calculation device Z inputs call data accumulated in a call data collection device X in a device unit when it passes a rate close date and executes a call rate account processing V. A package E recognizes that the call continues even after the user A or the user B on-hooks a receiver. A line between the packages E and F is opened in the stage of a restoration processing by periodical diagnosis and the detection of abnormality, and the call terminates when the package E restores to a normal state. The call rate account processing V executes rate account based on call data Xd and fault data Yd in the call data collection device X and a fault data collection device Y, Namely, call data satisfying the conditions of the call by using the package with a fault and a call whose call start time is before fault detection time and whose call termination time is after fault detection time is set to be out of a rate account object.