Introduction. Many researchers have indicated a need for interventions to improve self-awareness in people with acquired brain injury, but the intervention methods are still in its developmental stage. The purpose of this study was to investigate the effectiveness of an original awareness intervention using a single-case experimental design with each subject's individual occupation. Methods. We used the ‘alternating treatments design’, two types of interventions (ordinary occupational intervention and awareness intervention) were administered 10 times each (a total of 20 interventions) to four subjects. In the original awareness intervention, the subject participated in activities with self-prediction and self-evaluation before and after participating in activities and a therapist assists them to reinforce appropriate strategies. The Japanese version of the Self-Regulation Skills Interview (SRSI) was administered after each occupation experience, scores and responses for each of the ten interventions were compared between two interventions. Results. Three of the four subjects showed significantly lower SRSI scores in the awareness intervention that indicated their awareness were higher than the ordinary intervention and the details of their responses also indicated higher awareness during the awareness intervention. One subject who showed the lowest score of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) in the subjects didn't show any major change. Conclusion. The results would suggest the effective of the awareness intervention. Future studies require a larger number of subjects, and investigation of the necessary level of subject's cognitive functions.