Recently, due to an increase in children from diverse cultural and lingual backgrounds in Japan, arts activities that help them to maintain stable emotions and strengthen their sense of self-esteem have become as important as linguistic education. This study aims to clarify the effects of musical activities on foreign children living in Japan. Nine children aged four to eight years attending extracurricular Japanese language classes participated in a music workshop. A questionnaire based on the mood checklist was administered before and after the workshop. The results showed that the positive mood state (pleasantness, relaxation) decreased slightly, and the negative mood state (anxiety) increased, despite eight out of nine children answering, “I really enjoyed myself.” On individual examination, one of the children showed an increase in the positive mood state and a decrease in the negative mood state. Six children registered positive mood changes or maintained the highest score for positive mood or the lowest score for negative mood. The two children did not exhibit any productivity. Based on the results of the mood checklist and the children’s individual situations, most of the children had some positive changes after the workshop. In conclusion, the results suggest that musical activities can positively affect children’s emotions, and percussion performance can contribute to an increased positive mood with a feeling of satisfaction.