A facsimile apparatus having an automatic facsimile/telephone switching function, comprises detecting unit for detecting a high layer compatibility included in a setup message of an ISDN and control unit for immediately connecting the facsimile apparatus to a distant station when the high layer compatibility is indicating a facsimile apparatus. Thereby, in the case where the high layer compatibility is FAX, the FAX is immediately connected to the telephone line. Hence, the waste of time and wasteful bell sound can be eliminated.