As a new type of application of the conversation system, a robot activating other parties’ communications has been developed. The robot participates in a quiz game with other participants and tries to activate the game. The functions installed in the robot are as follows: (1) The robot can participate in a group communication using its basic group conversation function. (2) The robot can perform the game according to the rules of the game. (3) The robot can activate communication using its proper actions depending on the game situations and the participants’ situations. We conducted a real field experiment: the prototype system performed a quiz game with elderly people in an adult day-care center. The robot successfully entertained the people with its one hour demonstration.