The current study examined the effectiveness of mental health professional’s school visit service for intervention. The school visit service team consists of mental health professionals including psychiatrists, social workers, and counselors. 1,224 students, 984 parents, and 1,078 teachers responded to the evaluation survey. The effectiveness of the service was measured by SDQ-Kr, CGI-Severity, and CGI-Improvement. Students reported that their hyperactivity and negative affect decreased significantly, while parents reported that their children showed increase of positive social behavior as well as decrease of hyperactivity, negative affect, peer relationship problems and conduct problems. Teachers also reported that students showed increase of positive social behavior as well as decrease of hyperactivity, negative affect, and conduct problems. In addition, significant clinical improvement was identified among the participants of the service. Implications of the service were discussed based on the results and suggestions for futrue research were provided.