Face of a listener is photographed by a CCD camera, and a face width and auricle size of the listener are detected on the basis of the picture of the listener’s face. The amine bridged metallocene catalyst may be produced by reacting one or more of substituted or unsubstituted cyclopentadiene and substituted or unsubstituted fluorene with amine to bridge them with nitrogen, and reacting them with a transition metal to coordinate them. The folding machine further includes a phase adjustment assembly configured adjust the location of the fold in the sheet material, to locate the fold in a proper position on the sheet relative to the leading end of the successive sheet.