A method of predicting growth of a crack in a member comprising the steps, executed by an information processing device 100, of: memorizing, for each portion on the member, stress distribution Δσ(a) in the depth direction obtained in the case that no crack is present, a relationship between depth of growing cracks and creep contribution, and a relationship between creep contribution and parameters C and m of the Paris's law; receiving from a user an indication of a certain portion on the member; acquiring the stress distribution Δσ(a) in the depth direction for the certain portion; acquiring a creep contribution at the depth of a growing crack for the certain portion, from the relationship between depth of cracks and creep contribution memorized for the certain portion; acquiring parameters C and m corresponding to the acquired creep contribution, from the relationship between creep contribution and parameters C and m of the Paris's law memorized for the certain portion; predicting the growth of the crack in the certain portion, based on the following equations: da/dN = C × ΔK m, and ΔK = Δσ a × π × a 1 / 2 wherein "a" is a crack depth, N is a number of occurrences of a cyclic stress, C and m are constants determined for a member, and ΔK is a stress intensity factor range; and characterized in that when a curve representing the relationship between number N of the cyclic stresses and length "a" of a crack, the curve being obtained by predicting growth of cracks in the certain portion, has a steeply changing segment where the length "a" of the crack steeply changes relative to the change in the number N of the cyclic stresses, correcting the curve by drawing a tangent line on an upwardly convex portion of the steeply changing segment from the vicinity of the origin. memorizing, for each portion on the member, stress distribution Δσ(a) in the depth direction obtained in the case that no crack is present, a relationship between depth of growing cracks and creep contribution, and a relationship between creep contribution and parameters C and m of the Paris's law; receiving from a user an indication of a certain portion on the member; acquiring the stress distribution Δσ(a) in the depth direction for the certain portion; acquiring a creep contribution at the depth of a growing crack for the certain portion, from the relationship between depth of cracks and creep contribution memorized for the certain portion; acquiring parameters C and m corresponding to the acquired creep contribution, from the relationship between creep contribution and parameters C and m of the Paris's law memorized for the certain portion; predicting the growth of the crack in the certain portion, based on the following equations: da/dN = C × ΔK m, and ΔK = Δσ a × π × a 1 / 2 wherein "a" is a crack depth, N is a number of occurrences of a cyclic stress, C and m are constants determined for a member, and ΔK is a stress intensity factor range; and characterized in that when a curve representing the relationship between number N of the cyclic stresses and length "a" of a crack, the curve being obtained by predicting growth of cracks in the certain portion, has a steeply changing segment where the length "a" of the crack steeply changes relative to the change in the number N of the cyclic stresses, correcting the curve by drawing a tangent line on an upwardly convex portion of the steeply changing segment from the vicinity of the origin.