15. A robot control system according to claim 12 , wherein the storing module includes a completion storing module storing that the output of the utterance content is completed, and the outputting module outputs the utterance content different from last time when it is determined that the user to whom it is stored that the output of the utterance content is completed enters the predetermined range and that the direction of the user turns to the exhibition.
12. A robot control system according to claim 9 , further comprising a storing module storing that the utterance content is output to the user, wherein the outputting module outputs the utterance content different from the utterance content at the last time when it is determined that the user to whom it is stored that the utterance content is output and the direction of the user turns to the exhibition.