The purpose of this study is to analyze the process of how teachers and pupils share music and how pupils interpret pieces and express their intentions in singing activities. In order to elucidate this process, the study involved participate observations of choral practices by choir members at Gyosei Elementary School and semi-structured interviews with them. The data were analyzed based on the grounded theory approach. These qualitative data were classified into a main category, “The discovering and sharing of problems” and 7 sub-categories, ‘Perceiving surrounding sounds and their own voices,’ ‘Grasping characters of pieces of music,’ ‘Learning for understanding texts,’ ‘Coordinating their own singing with surrounding sounds,’ ‘Singing with integrated thinking,’ ‘Singing lacking expression,’ ‘Singing with expressive variation.’ In conclusion, the following two points were found to be salient factors : (a) Discovering the problems is important for pupils to perform music since the discovery of problems helps to interpret music. (b) It is important to share the discovered problems which are to create certain singing expressions in the community.