A communication apparatus capable of selecting proper facsimile communication according to a gateway of a connection destination. A communication apparatus that performs facsimile communication via a gateway connected to an IP network establishes a voice session for performing voice communication, with the gateway. When a T.38 session establishment request is received after the voice session has been established, the voice session is changed to the T.38 session to perform facsimile communication using T.38 communication. When the T.38 session establishment request is not received after the voice session has been established, facsimile communication using inband communication is performed by the voice session.