To improve convenience by surely informing a user of an incoming telephone call, and moreover, by automatically adjusting the volume according to the state of the incoming telephone call, convenience is enhanced.

When a determination result of an incoming call state determining circuit 19 is a presence of incoming call, a microcomputer 20 controls an image processing unit 16 to display information related to the presence of the incoming call. When the determination result of the incoming state determining circuit 19 is a start of communication, a sound output is controlled by making a sound processing unit 14 either turn down the volume to a predetermined level or silence the incoming call. When the determination result of the incoming call state determining circuit 19 is an end of communication, the sound output is controlled so as to make the sound processing unit 14 return to the volume of the original level value.