A chatbot server that manages context information between a chatbot and a user device includes a receiving unit that receives, from a messenger server, a question message input for a service selected from multiple services by the user device and service account information corresponding to the selected service; a derivation unit that derives an answer to the question message by using the chatbot corresponding to the service account information; and a context information management unit that manages context information of a chat between the user device and the chatbot based on the question message and/or the answer.