PURPOSE: To provide an automatic film switching device for a packing device capable of transferring a film continuously by enabling the switching through reliable film-connection.

CONSTITUTION: An automatic film switching device for a packer is provided with a film supply part 7 for delivering and guiding a supply film F delivered from a supply film roll R loaded on a holding frame 6 and a stand-by film F' loaded on a holding frame 6' in proximity to each other, and a rotation detecting part 12 for detecting the rotation of the holding frame 6 rotated in association with the continuous delivery of the supply film F. The automatic film switching device is further provided with a film connecting part 20 having a pair of pressure bonding plates 21, 21' movable in the opposed direction and locking pieces 23, 23' disposed at the upper parts of the pressure-bonding plates 21, 21' so as to temporarily fasten the starting edge part of the stand-by film F' and to support it in the stop state, a film terminal end detecting part 24 for detecting the terminal end part of the supply film F, and pressure-bonding plate actuating parts 26 for making the pressure-bonding plates 21, 21' individually movable.