A computer-implemented method for designing a spectacle lens for the purpose of manufacturing said lens, which, when executed on a computer, comprises the following steps: when rotational asymmetry of an aberration distribution of an eye of a wearer about an optical axis is strong, obtaining, as a design solution, a spectacle lens that has an aberration distribution of which rotational asymmetry is weak in a region having a predetermined width and a center at any point on a main meridian of the spectacle lens; when rotational asymmetry of the aberration distribution of the eye of the wearer about the optical axis is weak, obtaining, as a design solution, a spectacle lens of which rotational asymmetry is strong in the region; characterized in that, when an index that is obtained by quantifying rotational asymmetry regarding the aberration distribution of the eye is represented by Ei, a standard value of Ei is represented by Es, and an index that is obtained by quantifying rotational asymmetry of an aberration distribution of a spectacle lens is represented by Li, a spectacle lens of which Li is low is obtained as a design solution when Ei is larger than Es, and a spectacle lens of which Li is high is obtained as a design solution when Ei is not larger than Es, wherein Ei represents an index that is obtained by quantifying at least rotational asymmetry of an aberration distribution of a portion of a cornea corresponding to a pupil of the eye of the wearer, about the optical axis, and wherein Ei is an index expressed by the following Expression 1, and ∑ m, n mE m, n Li is an index expressed by the following Expression 2, ∑ m, n mL m, n wherein E and L respectively represent polar coordinate expressions of Zernike aberration coefficients of the eye of the wearer and the spectacle lens, m represents a value indicating an order in a circumferential direction, and n represents a value indicating an order in a radial direction. when rotational asymmetry of an aberration distribution of an eye of a wearer about an optical axis is strong, obtaining, as a design solution, a spectacle lens that has an aberration distribution of which rotational asymmetry is weak in a region having a predetermined width and a center at any point on a main meridian of the spectacle lens; when rotational asymmetry of the aberration distribution of the eye of the wearer about the optical axis is weak, obtaining, as a design solution, a spectacle lens of which rotational asymmetry is strong in the region; characterized in that, when an index that is obtained by quantifying rotational asymmetry regarding the aberration distribution of the eye is represented by Ei, a standard value of Ei is represented by Es, and an index that is obtained by quantifying rotational asymmetry of an aberration distribution of a spectacle lens is represented by Li, a spectacle lens of which Li is low is obtained as a design solution when Ei is larger than Es, and a spectacle lens of which Li is high is obtained as a design solution when Ei is not larger than Es, wherein Ei represents an index that is obtained by quantifying at least rotational asymmetry of an aberration distribution of a portion of a cornea corresponding to a pupil of the eye of the wearer, about the optical axis, and