The main issues addressed in this paper are as follows : First, this paper makes a distinction among types of e-money, IC card type versus Network type, open-loop type versus closed-loop type, online type versus offline type and accountable type versus unaccountable type, and analysis the clear and accurate criterion. Second, generally speaking, e-money is a claim on originator of e-money and not legal tender, so, delivery of e-money by itself does not relieve of monetary obligation. Because it is not easy to define e-money, by now there are many definitions of e-money. there is a legal uncertainty accordingly and then it is not easy to find proper law applicable to resolve a particular issue. As a result, many problems relating to e-money would be solved through analogical application of the most proper law among the laws that apply to the cash, checks, credit card, or fund transfer after analyzing type of e-money at issue. This paper studies the methods on diffusion of the utilization of electronic money. To diffuse the usage of electronic money, it needs prerequisitely as a basic conditions independence of electronic money, non-reusability, and anonymity. And also as a additional conditions it needs usability in the offline commerce, transferability, divisibility. And now electronic money is used very actively, but still has many law problems such as protections of consumer, law enforcement, supervisory, etc. So electronic money has called as money, but it is sure that electronic money is not a legal tender. So to facilitate the economic function of the electronic monet it is need to supplement the electronic money in the legal sides.