Our main goal in this research was to validate the possibility of virtual reality (VR) for attention enhancement in cognitive training program. Then, we developed some cognitive training tasks using VR technology. Thirty subjects who had little behavioral problems and social problems were randomly assigned into three groups: VR group, non-VR group, and control group. Only the VR group used the head-mounted display (HMD) and position sensor. While the VR group and non-VR group performed cognitive training, the control group received no special treatment. All participants took their eight session tasks over 2 weeks. Participants executed a continuous performance task (CPT) before and after training sessions. We found that immersive VR with cognitive training is effective for attention enhancement. Also, we confirmed that our cognitive training can improve the attention span of children and adolescents with behavioral problems and help them learn to focus on some tasks.