PURPOSE: To facilitate removal of a sound absorbing material from the inner surface of a package by providing a knife with a metallic handle for peeling a sound absobing material having a source cord for a sheet heater, and mounting a sheet heater the metallic surface temperature of which is heated to 60-90°C.

CONSTITUTION: Since a metallic part 2 of a knife l with a metallic handle for peeling a sound absorbing material is always heated by a sheet heater 4, a metallic part 2 surface is kept at a specified temperature or more. Thereby, an adhesive by means of which the sound absorbing material 8 is adhered to a package 9 can be easily peeled from a package surface by means of the heat of the metallic part 2 surface.