PURPOSE: To decrease invalid processing in the case of selecting an idle line at the time of concentrating calls and to decrease time required for line connection by providing the idle judge inhibit time deciding means of a repeating line group and an idle judge inhibiting means.

CONSTITUTION: When all the lines housed in a repeating line group 9a are made busy, the repeating line group 9a is put out of a selective object until the lapse of time, and this is shown to a table. Namely, the idle judge condition of the repeating line group 9a is turned to an inhibited state. When any call from a PBX 2 to an PBX 4 is generated in such a case, the call is connected by using the table. Namely, the idle judge of the repeating line group 9a is ignored for the call to be connected from the PBX 2 to the PBX 4, and it is started from the idle judge of lines housed in a repeating line group 9c. Afterwards, the repeating line group making all the lines busy is temporarily put out of the selective object unit the lapse of time shown in the table, namely, so as to expect the line is made idle, and added to the selective object again after the lapse of this time. Thus, invalid processing at the time of line selection can be decreased.