To encircle tension rollers with a packaging material in a quick, easy and simple manner to pass it around the tension rollers in a tensed state in a stretching head of a film packaging machine.

A drive means for tension rollers 44, 46 is disposed at one of ends of a stretching head 10, and the other opposite end of the stretching head 10 is formed in an open state at all times. A packaging film material 18 is designed so as to be insertable between the tension rollers 44, 46 in an axial direction. By inserting the packaging film 18 in a direction parallel to the center axes of the tension rollers 44, 46, both the tension rollers 44, 46 are quickly and easily spread all over the packaging film 18, and the packaging film 18 is passed aroung the tension rollers in a tensed state.