Brain-computer Interfaces (BCIs) and robots hold great potential for enhancing focus in tasks and acting as educational agents. In this research, we propose to create a robot alert system that helps improve user’s concentration by alerting the user when their concentration drops. The user’s concentration is detected by their brain activity using a commercially available electroencephalograph (EEG) sensor. This paper presents our design and development of the proposed EEG-based robot alert system using voice and facial expressions. To investigate the possibility of improving user’s concentration, we evaluated the developed system by carrying out an experiment to improve user’s concentration while learning. This was evaluated by monitoring the user’s concentration using EEG while watching an educational video with and without our proposed robot alert system. The experimental results show the user’s concentration levels to increase after the alert, thereby suggesting that our EEG-based robot alert system successfully improved the user’s concentration. Our alert system contributes to improving user’s concentration in situations that require cognitive thinking such as e-learning and driving.