This study investigated the effects of structured instrument-playing on the improvement of subjective happiness and the reduction of depression of the elderly in residential care. The experimental group consisted of 10 elderly people from S residential care in city “J,” and the control group had 10 elderly people from C, S residential care in city “J.” Before implementing the structured instrument-playing, the subjects were pre-tested to obtain measures of their subjective happiness and depression levels.
 For the experimental group, the experimental procedure was carried out for a total of 14 sessions, 50 minutes each, during the period of February 13 to March 31, 2017. After these sessions, post-tests were conducted to both groups to track any changes in the participants’ subjective happiness and depression levels. Following is the summary of the major findings: First, structured instrument-playing appeared to have a positive effect on improving the subjective happiness of elderly people in residential care. Also, the data also showed that structured instrument-playing had a positive effect on the participants’ inner happiness, external happiness, and self-control happiness. Second, structured instrument-playing also had a positive effect on reducing depression of elderly people in residential care. By proving that this study works, the findings of this study suggest that structured instrument-playing program can be effective for improving the elderly residents’ subjective happiness and depression. Also, the study suggests that structured instrument-playing can be applied to improve the effectiveness of programs for not only the elderly in residential care but also to nursing home elderly, frail and dementia elderly.