The present invention provides a shared phone, a medium having recorded therein a program for controlling the shared phone, and a method for controlling the shared phone, which can make the shared use by a plurality of users easy. The shared phone switches phone numbers depending on users, and includes a user information storage unit that stores user information including phone numbers for each user, a public line communication unit that performs public line communication, and registers phone numbers stored in the user information storage unit to a public line, and detects an incoming call to a registered phone number, a display unit that, in case an incoming call is detected by the public line communication unit, displays user information corresponding to the incoming call from among user information stored by the user information storage unit, and an operation unit that accepts instruction for public line communication from a user, and sends the instruction to the public line communication unit.