Trials on the transmission of olfactory information together with audio/visual information are currently being conducted in the field of multimedia. However, continuous emission of odor creates problems of human adaptation to the lingering olfactory stimuli. To overcome such a problem we developed an olfactory display. This display has high emission control so that it can provide stable pulse emission of scents. We previously proposed two scent presentation methods synchronized with the user's breathing pattern. The first method presents smell using a breath sensor. The second method presents smell using the ejection interval δt, determined by the olfactory characteristics. The results of evaluation experiments and a questionnaire survey of users revealed the proposed methods provide a continuous sense of smell to the user, avoiding adaptation.