There are few studies on the characteristics of defaulters, though research in this field is needed. The purpose of this study was to find out social, economic and psychological characteristics of defaulters who are married and in their thirties. For this study, an in-depth interview was used. The major findings were as follows. The focus of this study is defaulters who are married, in their thirties, have managed small businesses by themselves or with their spouses and have experienced job fluctuation. There were a lot of reasons for their becoming defaulters. Most of all, a slump in business with the occurrence of individual events caused them to be enrolled as defaulters. The monthly mean income of defaulters was $1,800,000{\sim}5,000,000$ won, yet it was irregular. Moreover, they were dependent upon labor income or business income. The monthly mean expenditure of defaulters was $1,000,000{\sim}2,300,000$ won, which constituted about $26%{\sim}57.5%$ of their monthly mean income. The defaulters needed to budget a number of expenditures such as food and private education. Defaulters had $25,000,000{\sim}128,000,000$ won in debts and $300,000{\sim}3,000,000$ won per month in debt payments. Most of them didn't have any emergency funds, monetary assets or fixed assets. Interestingly, they showed high tendency to use debt and low skill for their money management. Defaulters had short time horizons and were likely to buy something on the spur of the moment.