A conversation scenario editor generates/edits a conversation scenario for an automatic conversation system. The system includes a conversation device and a conversation server. The conversation device generates an input sentence through speech recognition of an utterance by a user. The conversation server determines the reply sentence based on the conversation scenario when a reply sentence to the input sentence is requested from the conversation device. The editor includes a language model generator for generating a language model to be used for the speech recognition based on the conversation scenario. According to the editor, a non-expert can generate the language model to provide an adequate conversation based on the speech recognition.