To make a pattern on the surface of a mat by transforming pile and to make unnoticeable a cigarette burn on a doormat for rent.

A shield panel 3 with a pattern cut out is put over the surface of a doormat and a hot air is blown on it, thereby the pile exposed to the hot air getting crimpy. In this way a pattern can be formed on a mat at a low cost, durable term of a doormat for rent can be extended and the pile on the surface of a mat is hardened, thereby brushing effect being improved to remove dirt on the shoe sole.