To provide a charges processing system and a charges processing method which effectively increase the frequency in use and the use time of a telephone line to realize promotion of use of the telephone line.

The charges processing system provided with a line usage management means 7 which counts line usage at the time of originating a call, a charges calculation means 8 which calculates the charges in accordance with the counted line usage at the time of originating, and a charges database 9 where the calculated charges is registered as usage charges is provided with a line usage management means 11 which counts the line usage at the time of terminating a call and a discount application means 12 which determines a discount rate based on the counted line usage at the time of terminating the call applies a discount to the usage charge registered in the usage charge database 9.