A method of measuring a refractive index distribution includes steps of setting a plurality of different arrangements by a translation movement in a state where an object is arranged in first and second media having refractive indices different from a refractive index of the object, measuring transmissive wavefront of the object for each of media and each of the plurality of arrangements by reference light entering the object (S400), obtaining wavefront aberration corresponding to a difference between each transmissive wavefront and a reference transmissive wavefront (S500), obtaining refractive index distribution of the object by removing an influence of a shape error of the object using wavefront aberration of two media in which the object is arranged at the same position (S70), and obtaining refractive index distribution information of the object based on a plurality of refractive index distributions corresponding to the plurality of arrangements (S80).