To provide an electronic commerce system in which whether or not a product selected fits oneself can be confirmed without directly wearing.

The electronic commerce system has a server 1 having a data base comprising size information of a body of a user and a data base comprising size information of products, a sense of fitness determining engine 4 comparing a size of a product specified by the user with a size of the body of the user, user terminals 6-1 to 6-N for confirming a comparison result, and a graphics engine 3 generating a two-dimensional or three-dimensional image of the body of the user on the basis of the size of the body of the user, overlapping an object of the product on an object indicating the user, mapping a texture of the product selected by the user on the object of the product and generating an image for display.