To reduce the connection time of a communication channel to recognize a communication mode of an opposite party, when executing a specific information processing mode with a specific opposite party and to decrease the communication charge relating thereto.

This communication device 100, that uses a telephone number notice service of a communication enterprise to process information of an optional opposite party or a center terminal 101, is provided with a comparison means 11 that compares whether or not a telephone number of the center terminal 101 having been registered in advance matches with a telephone number reported from the communication enterprise, and an information processing means 13 that connects the center terminal 101 to a communication line 1 to execute a remote diagnostic mode 7, when the telephone number of the center terminal 101 matches with the telephone number reported by the communication enterprise according to the comparison result of the comparison means 11 and that connects a terminal with the telephone number reported by the communication enterprise to the communication line 1 to execute a facsimile mode, when the telephone number of the center terminal 101 does not match with the telephone number reported by the communication enterprise.