It is one of the e-commerce that contracts and settlement are done through the Internet, and the general consumer buys goods etc. It is an abbreviation of Consumer to Consumer (consumer Martou consumer) and is also denoted by c2c. Internet auctions are a typical example of the popularity of the internet, which symbolizes the fact that consumers and consumers can easily buy and sell goods. As an example of CTOC other than the internet auction, there is a case to collect the use fee by providing the mechanism of the online shop including the payment system to be able to run the sales site which makes a personal sale easily. Such an operator is called a CTOC business person. In addition, there is a trader like PayPal which corresponds to the online payment for the individual, and it has come to be able to do electronic payment and the operation of the online shop easily even if it is a general consumer. More cases to broker the settlement of the proceeds, although it is changing into a form that is not buying and selling of the original consumer, the sense of security in terms of management of payment information and personal information increases, it is also established as a distribution system.