Oral administration of chloral hydrate with hydroxyzine, nitrous oxide inhalation and intramuscular or intranasal administration of midazolam is the most commonly used pharmacological behavior management methods for the children in pre-cooperative stage or show negative behavior in pediatric dentistry. For oral administration of chloral hydrate with hydroxyzine, it is hard to apply to the patient refused to intake and with overweighted or elderly children and the effect of the drug decrease. Nitrous oxide and midazolam is anxiolytic agents and have limitation for properly managing the behavior of the children refuse to dental treatment. These occasions, deep sedation or general anesthesia can be considered. Although intravenous sedation with midazolam has many advantages such as, rapid onset and recovery, possible to titration and few side effect, no rebound effect by metabolites, the reports for, intravenous sedation with midazolam is insufficient in pediatric dentistry. We report the case in pre-cooperative stage. He is treated successfully under intravenous sedation with midazolam.