in an image card where an image is formed on a thin plate made of special synthetic paper or plastic by engraving by sweeping the plate with the engraving needle through relative movement of an engraving needle and a plate , it is impossible to form a hidden image which can be viewed when a viewpoint is changed or form an image formed by watermark engraving and the hidden image within the same plane . a hidden image is formed on an image card by engraving while angles of stripes of striped patterns are changed in response to shading of an image . further , an image engraving device is provided with a rotary driving unit , and engraving is performed in a state that an extending direction of striped grooves of the hidden image and a forming direction of the engraving are made equal , so that a wall face of a groove is always formed by the same side face of an engraving needle and undulation does not occur on the wall face of the groove . similarly , a shape of a bottom face of the groove is made even . as a result , precision of the hidden image is made high and an effect as the hidden image is further improved .