The purposes of this paper are as follows: 1 a cause of over-indebted debtor problem occurrence by analysis based on contract theory and adaptation rationality.2 to suggest a countermeasure in education and system to prevent that occurrence. Concrete countermeasures are: 1 We must dissolve the non-symmetry of the information between the creditor, debtors in system 2 We should carry out EQ education to develop the adaptation rationality.
