PURPOSE: To facilitate the collation of the charging information between both networks A and B by generating detailed information by networks A and B based on the same information in the way that when the network A collects the calling information extended over networks A and B and judges the collected information corresponds to a callating object sample, the network A transmits the judgement to the network B by adding and displaying to that effect and the network A and the network B generate the detailed information based on the same information.

CONSTITUTION: A call setting request transmitter means 2 of a network A detects the calling information extended over networks A and B and decides whether or not these calling information correspond to a collation object sample Sv extracted in the network A by an Sv extracting means 1. If so, an originating call station detailed information generating means 3 adds the display to the effect that the calling information is selected as Sv and also adds the series numbers to the display to facilitate the analysis when the detailed information is generated at every call added with the Sv display. Then the means 2 transmits the information on the Sv to the network B together with call setting information to inform an incoming station detailed information generating means 5 of those information. The means 3 prepares the detailed information at every call added with the Sv display like the means 3. Thus the Sv displays of the detailed information are coincident with each other and the collation of charging information is facilitated between both networks.