In the present study, it aimed to execute Informal Assessment of TTAP that was the inspection to aim to understand object person's detailed realities in the starting work site and the region in practical training, and to examine the effectiveness. Prior duty experience, guidance in school based on the result, record for training period of three days, and evaluation on the final day of training were executed to two students with autism spectrum disorder of the second grader in high school divisions of a special needs school. As a result, each student acquired two or more skills through the training. Moreover, it was suggested that the practical training have advanced smoothly than so far from the questionnaire and the interview to the charge teacher and the training site staff by executing Informal Assessment of TTAP. On the other hand, those problems how to execute prior duty experience, how to record under training, and clarification of criterion of skills etc. were shown. It is future tasks to expand the case where TTAP is used by practical training, and to do more objective evaluation concerning the effect of use of it to work support.