Hand gesture input has been of growing importance in 3D content and VR/AR. However, a hand gesture detection system by camera was small in scope. And EMG was affected by noise from other electronic devices. Muscle deformation sensor system could only detect large muscles deformation related to wrist gestures because the sensor is covered to prevent light leakage noise. In this research, a device that covers the only sensor side circularly as light noise reduction case and has 14ch photo reflector sensors can detect small muscles deformation: FirstVR is suggested (Fig1, 2). Results of our experiment shows that recognition accuracy average of more than 90% is achieved with three types of PIP joint angles. In the future, FirstVR is expected to be used not only for content inputting finger movements indoors and outdoors but also for muscle displacement recording system.