[Purpose] A simple rehabilitation device system for strengthening upper limb muscles in hemiplegic patients was developed. This system, which stimulates active exercise while accounting for intensity, time, and frequency, was examined in the present pilot study. [Subjects and Methods] Patients had shoulder pain and limited shoulder movement. Changes in range of motion (ROM) and scores of a visual analog scale (VAS) for pain were evaluated in the experimental and control groups every four weeks for twelve weeks. The modified motor assessment scale (MMAS) was used before and after experiments. [Results] Significant differences between experimental times in ROM for shoulder flexion, abduction, and adduction on the paralyzed side were observed in the experimental group at every time point. Pain VAS scores in the experimental group improved progressively and significantly with time, indicating a consistently increasing effect of exercise. There were significant differences between the MMAS scores before and after completion of the program in the experimental group. [Conclusion] Muscle strengthening is important in hemiplegic patients, and active exercise was more efficient than passive exercise in this regard. Rehabilitation with the Monkey Chair and Band system may represent an efficient and important tool in upper limb training and comprehensive modern rehabilitation therapy.