a method of micromachining polytetrafluoroethylene by applying radiation light to the surface of polytetrafluoroethylene , includes the steps of : preparing a workpiece including a region made of polytetrafluoroethylene ; preparing a mask having patterned areas substantially transmitting and not transmitting the radiation light ; and applying the radiation light containing at least ultraviolet rays of a wavelength of 160 nm to a surface of the workpiece through the mask . polytetrafluoroethylene can be microscopically processed , while obtaining a high aspect ratio and processing a large area with ease .