To provide an image forming method which contributes to reducing an amount of waste paper documents which becomes useless immediately after being read, and is capable of temporarily forming and erasing an image.

The image forming method of this invention comprises: a process (a) that provides a medium capable of re-creating an image containing a base material and a photochromic material; a process (b) that exposes a medium to the light for image creation corresponding to a predetermined image, and provides an exposure region and a non-exposure region, and includes a process in which there is a color contrast between the exposure region and the non-exposure region, and a temporary image corresponding to the predetermined image can be viewed with eyes for a period when the image is visible; a process (c) that erases the temporary image by putting the temporary image to indoor ambient conditions for a period when the image is erased without using an image erasing device; and a process (d) that, depending on the circumstances, repeats the processes of (b) and (c) for a number of times.