To reduce the number of times of operation from a telephone set for setting the start register state of service by enabling a batch processing by dividing one part of contracted service registered by a subscriber into groups, so as to be set during start/cancel through an electronic exchange corresponding to a request from the subscriber.

In an electronic exchange 1, a controller 4 analyzes a special number inputted by a subscriber 2 and judges a registration request, cancellation, unit start registration or unit start cannel of service group. Based on this result, the controller 2 analyzes the inputted service number or service group number and judges either the contracted service or the existent service group. In case of YES, the controller 4 performs the setting or erasure of service group number, according to corresponding information in a data memory 5 or sets start or cancel to the start register state of that service class. Thus, the number of times for operating a telephone set ca be decreased.