Abstract: Disclosed is a dialogue processing system using speech act control, the dialogue processing system comprising: a main speech act unit which processes a free speech act and performs speech act control such that the free speech act returns to a main speech act, thereby processing a multi-turn dialogue in a consistent manner, and which processes a purposed utterance having a set purpose, for reaching a final dialogue objective; and a free speech act unit which processes a free utterance deviating from the purposed utterance and performs control such that the free utterance returns to the main speech act unit by searching for a node capable of returning to the purposed utterance.