To extract an improvement factor superior in cost effectiveness for improving the whole satisfaction degree by taking into consideration the relationship between an improvement in the whole satisfaction degree and the cost required for improving its whole satisfaction degree in improvement of every individual factor.

This improvement factor determining device 1 calculates a standard partial regression coefficient on the basis of an individual factor evaluation value indicating evaluation for every individual factor and the whole satisfaction value indicating the whole satisfaction degree, and calculates a value of the individual factor evaluation value required for improving the whole satisfaction value on the basis of the standard partial regression coefficient, and calculates the cost for improving the evaluation of the individual factor by the value of the calculated individual factor evaluation value on the basis of cost information, and determines the cost required for improving the whole satisfaction value on the basis of the calculated cost in response to accumulation of the individual factors and its combination.