An instant film pack includes a plurality of instant photo films. A case contains the instant photo films being stacked. An exit slot is formed in the case, for exiting the instant photo films to an outside of the case one after another. A claw path opening is formed in the case, for receiving insertion of an advancing claw mechanism for advancing the instant photo films by one photo film to move to the exit slot. A thrust preventing flap is disposed on an inside of the exit slot, for closing the exit slot at the middle, to prevent the instant photo films from coming through the exit slot. Furthermore, a light shielding sheet of aluminum foil closes the claw path opening in a light-tight manner, and is released to open the claw path opening upon advance of the advancing claw mechanism.