To flexibly extend the scale and function of a paging system which broadcasts sound from a loud speaker toward a prescribed area.

A broadcast server 10 in which a content that is to be broadcast when an event occurs in a production facility is previously recorded determines whether broadcast using IP telephones 2, 3a and 3b is being performed. When the event occurs in the production facility while broadcast using the IP telephones 2, 3a and 3b is being performed, it is determined whether broadcast using the IP telephones 2, 3a and 3b is to be interrupted in accordance with the priority of the occurred event. Thus, broadcast based on sound that a user emits and broadcast based on sound which is previously recorded are smoothly performed, thereby realizing the paging system with a large scale and multiple functions easily and inexpensively.