To provide a cutter for unsealing a paper pack such as for milk.

This paper pack cutter is provided with a part held by hand like an eyeleteer, and a metal fitting (tip is pointed sharply) mounted on the forward end thereof, a part of the metal fitting is provided with a knife edge 5 for cutting the paper pack. In opening a filling port, the pack cutter is reversed by the principle of lever so that a non-slip stopper 3 (this is fitted with a knife edge 4) is mounted in a portion of the paper pack cutter as a starting point.