A method for re-tracing an end point of an image by an image processing device for converting the line images of the image data into vector data in a semi-automatic way by tracing plural line images and converting them into one vector data. The method for re-tracing the end point of the image involves tracing the line images by transferring the tracing points on the line images and continuing the previous trace processing for re-tracing the line image which follows by waiting for an instruction to re-trace from the input unit and entering the instruction to re-trace the image specified for re-tracing when the tracing point has reached the end point of the line image whose tracing points have been traced.