A simulation system for providing a wearer with simulated experience of an eye image observed when wearing a spectacle lens, characterized by comprising: a spherical component parameter calculating means for calculating a spherical component parameter based on a spherical surface, chosen from parameters being a basis of the scaling of the eye image observed when wearing the spectacle lens with at least one of optical surfaces aspherical, a correcting component parameter calculating means for calculating a correcting component parameter caused by adding correction to the spherical component parameter, an aspherical component parameter calculating means for calculating an aspherical component parameter based on the spherical component parameter and the correcting component parameter, a simulation image generating means of generating a simulation image representing the scaling of the eye image observed when wearing the spectacle lens, based on lens location information when wearing the spectacle lens and the aspherical component parameter, and a simulation image displaying means for displaying the simulation image, wherein the spherical component parameter includes origination information (y 1s '(y,z),z 1s '(y,z)) and gradient information (k ys (y,z),k zs (y,z)) calculated by ray trace, the aspherical component parameter includes origination information (y 1 '(y,z),z 1 '(y,z)) and gradient information (k y (y,z),k z (y,z)) which is obtained by adding the origination information and gradient information of the spherical component parameter with the respective correcting component parameter and the lens location information includes information regarding a distance between at least a part of a portion forming the wearer's eye shape and the eye side surface of the spectacle lens. a spherical component parameter calculating means for calculating a spherical component parameter based on a spherical surface, chosen from parameters being a basis of the scaling of the eye image observed when wearing the spectacle lens with at least one of optical surfaces aspherical, a correcting component parameter calculating means for calculating a correcting component parameter caused by adding correction to the spherical component parameter, an aspherical component parameter calculating means for calculating an aspherical component parameter based on the spherical component parameter and the correcting component parameter, a simulation image generating means of generating a simulation image representing the scaling of the eye image observed when wearing the spectacle lens, based on lens location information when wearing the spectacle lens and the aspherical component parameter, and a simulation image displaying means for displaying the simulation image, wherein the spherical component parameter includes origination information (y 1s '(y,z),z 1s '(y,z)) and gradient information (k ys (y,z),k zs (y,z)) calculated by ray trace, the aspherical component parameter includes origination information (y 1 '(y,z),z 1 '(y,z)) and gradient information (k y (y,z),k z (y,z)) which is obtained by adding the origination information and gradient information of the spherical component parameter with the respective correcting component parameter and the lens location information includes information regarding a distance between at least a part of a portion forming the wearer's eye shape and the eye side surface of the spectacle lens. <EOS>