A communication server device that mediates communication information transmitted and received between a plurality of communication terminals provides people who are participating in a conversation using real-time chat with information that can create a trigger to prompt them to end the conversation. Included are a chat log update unit (13) that causes a chat log DB (15) to update and store communication information transmitted or received between a plurality of communication terminals in association with information of transmission or reception time; a conversation duration update unit (14) that causes a conversation duration DB (16) to update and store a duration from the time when the information is stored in the chat log DB (15); and an ongoing conversation determination unit (12) that presents, based on the duration stored in the conversation duration DB (16), interruption information related to the duration to the plurality of communication terminals in response to receiving a request to end transmission and reception of the communication information from at least one of the plurality of communication terminals.