Ankle brace is commonly used to treat and prevent ankle sprain. Its main aim is to restrict supina tion of the ankle. However, some braces restrict ankle dorsiflexion and plantar flexion. In addition, loosening and loss of restriction after exercise have also been reported. The purpose of this study was to reveal if thin-type ankle brace for ankle sprain restricts ankle dorsiflexion and plantar flexion and its effect of exercise. Five male adults (average age of 30.8±5.2 years) were included in the study. Dorsiflexion and plantar flexion of subjectsʼright ankle was measured before and after wearing the brace, and before and after exercises. Exercises consisted of perform ing 20 times of calf raise, full squat, maximum vertical jump, and 5-minute running on a treadmill. Measurement was performed thrice, and their average was statistically analyzed between with and without the brace, and be fore and after each exercise. The results showed that there was no significant difference between all measured an gles of with and without the brace and before and after each exercise. Thin-type ankle brace for ankle sprain have been reported to restrict supination. Considering our results, this brace does not restrict ankle dorsiflexion and plantar flexion.