To provide a time-saving and inexpensive method for forming a woven pattern subtly colored and shaded, three-dimensional, and allowing its finish form to be easily imaged, and to obtain a recording medium storing pattern data to be input into a loom.

This method for forming a proper pattern by a loom according to input pattern data comprises: subjecting an original data for pattern 1 for a proper woven pattern to dither treatment; and then converting the original data into the pattern data. The recording medium of the invention is to store a pattern data designed to make the loom form the proper woven pattern, wherein the original data for pattern 1 for the woven pattern is subjected to dither treatment and further converted into the pattern data.