To facilitate a work to remove pieces of garbage bags entwined around bag-cutting shafts.

In this device, two bag-cutting shafts 6, 6' are arranged in parallel in a bag-cutting room 3 provided with a charge hopper 4 at the upper position and a discharging port 5 at the lower position. Plural arms 16, 16' provided with bag-cutting blades 17 at the tips are fit to the shafts 6, 6' in radial patterns at prescribed intervals in the axial directions so that the tips of the blades 17 of the arms fit to one of the shafts are approached to the other of the shafts 6, 6'. When the shafts 6, 6' are rotated at different number of rotation, the pieces of the garbage bags entwined around the shafts 6, 6' are cut up and easily removed, since the tips of the blades 17 are rotated so that they rake the surfaces of both shafts 6, 6'.