The scientific development of Republic of Korea ranks the 5th position in the World. The laws on internet primary bank or internet only bank, however, has not been effective. On 2009, the Korean Financial Supervisory Commission is going to preparing legal basis for the bank. An internet primary/ only bank is the internet site of existing bank with physical offices or it may be internet based only. Virtual banks don't have branches or own ATM machines, so customers make deposits electronically or by mail. The bank may reimburse consumer's ATM fees for using other banks' machines. However, there may be a limit to the number of transactions a virtual bank is able to cover. An internet primary/ only bank offers of some or all the same types of accounts and services that traditional bricks-and-mortar banks do, but they typically charge lower fees and pay higher interest because of low overhead. The author introduces foreign web bank cases as well as some legal issues. Especially for the legal issues, the author insist to draw a clear line between the internet only bank and bricks-and-mortar bank. This is because of, in Korea, a bank is going to be chartered as an internet-only-bank but not as a bank. So, the "internet-only" means more than a business model in Korea. The author also insists some other legal issues which includes "non-bank-bank" issue. The possibility of the appearance of non-bank-bank is the same as in the United States in 1980s. The financial institution that did not meet the legal definition of a commercial bank, and thus avoided the prohibition against branching across state lines. Korea Banking Law currently has the same loophole. Finally, the author introduces the "niche bank", and suggest Korean Financial Regulatory Authority to induce future internet only banks to have a preference for a business model: like environment bank, micro finance, and so on.