Abstract: A horizontal type of packing machine with an adjustable pouch former, in which a guide screw having half left-handed threads and half right-handed threads is used for adjusting the width of the pouch former; a cylindrical gear is in mesh with two gears to drive a left and a right gear racks and to simultaneously adjust the height of two guide plates on both sides of the machine in order to adjust the height of the pouch former. According to the design of replaceable paper-guiding plates, a user can select the proper paper-guiding plates in accordance with the products and the packing paper for the purpose of increasing the function of the pouch former; the metal plate parts are used for forming a near quadric chain assembly by means of a rotary connector so as to have such parts moved and adjusted upon the adjustment of the pouch width.