The telephone relay device (30) is communicably connected to a teleconference server that relays an audio call between communication terminals participating in a teleconference via an IP network. The telephone relay device includes: a participation request unit (32) that requests the teleconference server to permit participation in the teleconference in response to receiving, from the teleconference server, an audio quality reduction notification indicating that audio quality of the audio call between the communication terminals becomes less than a predetermined level; a call making unit (33) that makes a call to a telephone terminal associated with the communication terminal in response to being permitted to participate in the teleconference; and a call relay unit (34) that relays an audio call of the teleconference between the telephone terminal and the teleconference server in response to receiving a response to the call from the telephone terminal.