A communication assistance device (10) includes a communication level determination unit (11) and a topic recommendation unit (16) so as to determine a level of a relationship between users who communicate with each other and provide communication assistance using the result of the determination. The communication level determination unit (11) determines the level (communication level) of the relationship between the users based on similarity between the users obtained from preference information showing preferences of the users, and on user action records showing records of actions taken by a certain user toward a partner user with whom the certain user communicates out of the users. The topic recommendation unit (16) selects, from among a group of topics prepared in advance, a topic that can be transmitted to the partner user based on the determined level of the relationship between the users and on preferences of the certain user and the partner user.