This is a variant on what is known as pearl milk tea, bubble tea or boba milk tea in the US, and which originated in Taiwan. This product is a mango Calpis drink line extension, packaged and distributed under the Elbee brand, the Asahi company which handles paper packaging. The "bubbles" are tapioca flavored konjac balls which are chewy, fun to eat and provide a certain sense of fullness. エルビー アサヒ タピオカ カルピス
Photo is a web capture for explanatory purposes, copyright belongs to the company.