Provided is a method of providing an unmanned dialogue service according to an embodiment of the inventive concept. The method includes transmitting or receiving text message data constituting a dialogue to or from a user terminal in an unmanned dialogue model, analyzing the dialogue to determine whether a counselor switching situation has occurred, transmitting a dialogue handover request including information regarding the dialogue to a counselor management apparatus when it is determined that the counselor switching situation has occurred, and automatically switching into a mode for relaying transmission or reception of messages between the user terminal and a counselor terminal that receives a task for processing the dialogue handover request allocated by the counselor management apparatus.