To provide a paper tube cutting device for making push-cut of a rotating paper tube capable of performing cutting of various paper tubes having different diameters without replacing the core.

The cutting device for paper tube A is structured so that the paper tube A is fitted on the core 1a or 1b in the draw-insert position X, the core 1a or 1b is moved to the cutting position Y, and the paper tube A in the cutting position Y is cut by a blade 16, wherein various cores 1a and 1b having different diameters are installed on a rotary disc 9 in such a way as arranged on one circumference centering on the axis of the rotary disc 9, and the arrangement of the cores 1a and 1b relative to the rotary disc 9 and the coordination between the cutting position Y and draw-insert position X are set so that when one core 1a/1b lies in the cutting position Y, the other core lies in the draw-insert position X, and thus paper tubes A of different diameters can be cut without replacing the core.