A traffic application amount calculation device 14 includes a calculation unit 143 that uses traffic data flowing to an IF of a NW device to calculate, in the IF, an average traffic amount in a transmission direction and an average traffic amount in a reception direction, a first arithmetic operation unit 145 that selects a direction in which an average traffic amount is smaller out of the transmission direction and the reception direction and calculates a standard deviation of the traffic amount in a selected direction that is selected, and a second arithmetic operation unit 146 that determines a traffic amount obtained by multiplying the standard deviation by a predetermined value as a traffic application amount to be applied to traffic in the selected direction.