PURPOSE: To easily duplicate a relief pattern without defect, and easily manufacture an original plate even when the finally duplicated original plate can not be used by using a flexible material such as an acrylate plate as a base to be duplicated from a resist relief pattern plate.

CONSTITUTION: When a chromium mask 4 having a pattern 5 formed thereon and a photographic plate 3 having a positive resist layer 2 formed on a glass base 1 are arranged opposite to each other, and exposed from the chromium mask 4 side with an UV ray 6, the positive resist is exposed excluding the area of the pattern 5, and a relief pattern 7 is formed on the glass base 1. The duplicated plate of the chromium mask 4 and a plate having an ultraviolet ray hardening resin 9 dropped on an acrylate base 8 are arranged opposite to each other, and exposed from the acryl base 8 side with the UV ray 6. Then, the ultraviolet ray hardening resin 9 is hardened in the pattern form, and when the both are peeled, the acrylate base 8 can be easily peeled while it is curved since the acrylate base 8 is flexible and a release layer 10 is applied thereto.