To maintain or increase the number of customers by a carrier differentiating services from those of competitive other companies.

In a telephone rate calculation method for calculating, from an MA cord table 10, a call distance between an outgoing MA and an incoming MA of a telephone by using the MA cord table 10 managing MA quadrate section per MA cord and a rate table 20 indicating a billing rate corresponding to a call distance and a call time zone, for obtaining the billing rate from the rate table 20 based on the calculated call distance and the call time zone, and for calculating a call rate based on the obtained billing rate and the call time, a rate setting presence/absence information (i2) per MA indicating whether or not the rate per MA is set is recorded in the table 20, and two kinds of billing rates according to the presence/absence of the rate setting per MA are recorded in the rate table 20, whereby the telephone rate is calculated by adopting one of two billing rates of the rate table 20 based on the information (i2).