A shape data generation method includes: identifying, from among a plural vertices of a first shape to be transformed, one or plural first vertices satisfying a predetermined condition including a condition that a normal line of a vertex to be processed crosses with a second shape that is a shape of a transformation target, which is identified from image data; transforming the first shape so as to move each of the one or plural identified first vertices a predetermined distance toward a corresponding normal direction of the identified first vertex; and storing data concerning the plural vertices of the transformed first shape after the identifying and the transforming are executed the predetermined number of times.