PURPOSE: To eliminate the need to edit a zone which conforms to the installation place of a private branch exchange by storing a nationwide section number file in a storage device, and inputting a toll number.

CONSTITUTION: After a section number file SNF is stored in a storage device RAM, a toll number which corresponds a unit charge area wherein an automatic private branch exchange is installed is inputted from a console. A corresponding MPU having received the toll number refers to the section number file SNF stored in the storage device RAM to extract a rectangular section number which corresponds to the toll number. Then, the MPU claculates a charge distance from the extracted rectangular section number and that which corresponds to each toll number TN, thus finding a charging zone ZR according to a system. Then, the charging zone ZR is stored in a zone table CST in the RAM in the increasing order of the toll number TN.