To solve the problem that a hidden image which is visible by a difference of points of view can not be formed and that an image formed by an open work and the hidden image can not be formed in the same plane, in an image card in which an image is formed by engraving on special synthetic paper or a plastic sheet in a scanning form with a relative movement between an engraving stylus and a plate to be engraved.

A hidden image is formed by engraving an image card while changing an angle of stripes of a stripelike pattern in accordance with a shade of an image. The hidden image formed by this method and an image formed by a watermark are formed in the same plane.