A nasal cannula device includes a cannula body. The cannula body includes an accommodating chamber inside and includes two nasal joint tubes extended outwardly and communicating with the accommodating chamber. A junction ring is formed between the cannula body and each nasal joint tube. At least one of the cannula body and each nasal joint tube includes a recessed annular section recessed at one side of each junction ring. The recessed annular section has a thickness smaller than a thickness of the cannula body, a thickness of each nasal joint tube, and a thickness of each junction ring. Accordingly, the nasal cannula device can deliver a therapeutic gas smoothly.
