A method for setting shot-peening process condition comprising: obtaining, for each of a plurality of peening conditions for a first combination as a combination of a shot-peening processing apparatus and media, a saturation time based on a saturation curve indicating change in arc height value of Almen strip against projection time; and determining a first optimum peening condition corresponding to said first combination based on said saturation time, characterized in that condition factors of said plurality of peening conditions include: a first condition factor; and a second condition factor, wherein said plurality of peening conditions include: a first peening condition; a second peening condition different from said first peening condition in only a level of said first condition factor; a third peening condition; and a fourth peening condition different from said third peening condition in only a level of said second condition factor, and wherein said determining said first optimum peening condition based on said saturation time includes: determining a level of said first condition factor in said first optimum peening condition based on a first saturation time under said first peening condition and a second saturation time under said second peening condition; and determining a level of said second condition factor in said first optimum peening condition based on a third saturation time under said third peening condition and a fourth saturation time under said fourth peening condition. obtaining, for each of a plurality of peening conditions for a first combination as a combination of a shot-peening processing apparatus and media, a saturation time based on a saturation curve indicating change in arc height value of Almen strip against projection time; and determining a first optimum peening condition corresponding to said first combination based on said saturation time, characterized in that condition factors of said plurality of peening conditions include: a first condition factor; and a second condition factor, a first condition factor; and a second condition factor, wherein said plurality of peening conditions include: a first peening condition; a second peening condition different from said first peening condition in only a level of said first condition factor; a third peening condition; and a fourth peening condition different from said third peening condition in only a level of said second condition factor, and a first peening condition; a second peening condition different from said first peening condition in only a level of said first condition factor; a third peening condition; and a fourth peening condition different from said third peening condition in only a level of said second condition factor, and wherein said determining said first optimum peening condition based on said saturation time includes: determining a level of said first condition factor in said first optimum peening condition based on a first saturation time under said first peening condition and a second saturation time under said second peening condition; and determining a level of said second condition factor in said first optimum peening condition based on a third saturation time under said third peening condition and a fourth saturation time under said fourth peening condition. determining a level of said first condition factor in said first optimum peening condition based on a first saturation time under said first peening condition and a second saturation time under said second peening condition; and determining a level of said second condition factor in said first optimum peening condition based on a third saturation time under said third peening condition and a fourth saturation time under said fourth peening condition.