Approximately 10 years have passed since the words such as digital cash, digital money, electronic money, and e-cash have been introduced. Progress has increased rapidly in the fields of communication and information technology (IT) and in the field of digital cash; its use and transaction volume have been increasing. However, little analysis has been done about this phenomenon especially from the academic field. The continued increase in its use is inevitable, and it is important to investigate its influence and problems from both practical and theoretical perspectives. The spread of the use of digital cash impacts economic activity and social structure. This article considers both the merits and the problems of digital cash in the modern economy. This article analyzes characteristics of relationships between digital money, financial institutions, and financial authorities; considers the relation between digital cash and financial institutions; and analyzes the relation between digital cash and monetary policy authorities.