To provide communication device, communication system and communication method, capable of avoiding exceeding deterioration of communication quality and communication disconnection during IP communication, by securely switching from IP communication through an IP channel to communication through an appropriate channel.

A communication device 10 includes: IP communication means 11 for IP communication through an IP network; public switch telephone communication means 12 for public switch telephone communication through a public switch telephone network; particular event detection means 13 for detecting a particular event having high possibility of causing deteriorated IP communication quality; and control means 14 for, when the particular event is detected during IP communication, changing from the IP communication to public switch telephone communication.