To enhance flexibility through a user using a general-purpose client unit to enable communication of presence information with a presence information processing server.

In the presence information processing system including the presence information processing server for processing presence information related to telephone sets, the presence information processing server 30 includes: a general-purpose server unit functioning as a server for the general-purpose client unit; and a presence information storage section for acquiring and storing presence information of a telephone terminal used by the user or other telephone terminals via the general-purpose server unit, and when the telephone terminal included in a set of terminals has no presence information client unit being a function of communicating the presence information with the presence information processing server 30, the user uses the general-purpose client unit to make communication of the presence information with the presence information processing server.