SUMMARYIn the present article, a typical lip-sucking habit case is reported. An eleven-year-old male child has contracted the habit of sucking the left internal part of his upper lip during sleeping. Since 16 month of age as a result of this habit that part of the lip, as compared with the opposite side, peresented a more swollen, harder and deeper colaration as if giving the impression of a hemangioma.As the patient persisted, while sleeping, unconsciously in his habit, it was impossible to have recourse to a psychic suggestion.Due to the fact that no other orthodontic therapeutic means were available, an "oral screen" was applied.The appliance (oral-screen) was prepared in such a manner that it would not fall off the mouth without any effort.With the aid of this appliance whatever the effort of the patient, the sticking of the lip was impossible. In the course of the following up the patient, it became, at ones, obvious whether the appliance was used or not.According to the subjective history of his mother, the lack of the application, even for one night, was perceptible.In the oourse of a six-month-treatment, a rather satisfactory result was obtained, despite the occasional negligence of the use of the appliance.